Hoses for SCUBA

The Miflex™ extreme performance braided flex SCUBA hoses are manufactured in Italy with more than thirty individual performance and safety automated tests. We stock only black color hoses except for the 40-inch regulator hose, although Miflex brand low pressure hoses are manufactured in a rainbow of colors available from other retailers. Miflex hoses are distributed in the US by XS Scuba and are individually packaged with a reusable vinyl pouch.

DGX Premium braided flex SCUBA hoses are manufactured in Taiwan. The finished hoses are pressure tested by the manufacturers and each are again tested by us immediately prior to shipping to the consumer. The DGX Premium hoses are manufactured to our specification for length and thus are available in an exceptionally broad range of individual lengths. Our unbranded generic hoses have a lower retail price as a result of being sourced directly from the manufacturer in bulk packaging.

Cosmetics, construction, and flexibility of the low pressure braided hoses are similar with only minor differences between Miflex and DGX, but the high pressure versions are significantly different. The Miflex high pressure hose outside diameter is a third thinner, more flexible and includes protectors on the fittings to improve impact resistance. The DGX Premium high pressure hose includes a woven Kevlar layer creating a typical outside diameter that better fits consoles and boots.

All hoses are designed to meet CE EN250 standards and are Nitrox Ready. Our long experience with the branded Miflex and generic DGX Premium hoses has been both have similar reliability in the field. Regardless of brand, every product we sell is backed by Dive Gear Express 5-star quality customer service.

The choice is largely a matter of availability or personal preference, the price is about the same. Rubber hoses haven't changed significantly since the beginning of diving. Compared to rubber, the braided flex hoses (introduced in the early 2000's) are much lighter weight and much more flexible. Depending on hose lengths, a regulator setup using flex hoses is going to be about 2 pounds lighter than comparable rubber hoses. Some divers prefer the weight, but frequent flyers often choose flex over all other considerations when they want to travel as light as possible. Most divers in really cold water less than {50° F | 10° C} report the braided flex hoses perform much better than rubber.

Flex hoses are sometimes promoted as more durable than rubber and while true it is also irrelevant because you should replace your hoses every five years of service regardless. A few of the early flex hoses had an issue with the material of the inner lining, but that issue was addressed long ago and should not be a factor in your decision. Today, we can detect no difference in reliability for either material and we can also say that braided flex substantially outsells rubber. It's also worth pointing out that all our suppliers have now switched to braided flex hoses supplied with their regulators

Yes, we have a solution. BC integrated alternate air sources are sold under a variety of different brands and models, but often referred to generically as an "Air2" after the most common one. We offer high-flow adapters that allow any length standard regulator hose to be converted into a quick disconnect hose for BC integrated alternate air sources. For more information visit DGX Adapter: LP Reg Hose = BC Integrated 2nd Stage.

The first stages of modern SCUBA regulators have 3/8-inch 'Low-Pressure Ports'. The second stages of modern SCUBA regulators have 9/16-inch fittings to connect the regulator hose to the second stage body. These fittings are very standardized and your regulator almost certainly is compatible with these same fittings on our LP regulator hoses. However, there are a few rare exceptions: A few brands of first stages include one special low-pressure port that is 1/2-inch, notably some older Apeks, Dacor, and Mares models. For these rare exceptions we stock first stage port adapters.

Older Poseidon brand second stages are also a special case. Historically, Poseidon incorporated the OPV for their upstream second stages in a unique fitting on the end of their non-standard low-pressure second stage hose. In 2008 Poseidon updated their designs (the Mk3 designation) to no longer require a Poseidon-specific low-pressure regulator hose, but we do have a solution for using standard regulator hoses with vintage Xstream and Jetstream second stages. Cyklon regulators have unique hose compatibility issues and often require special hose fittings or adapters.

A few brands of second stages used with full face masks have a unique fitting, notably the Interspiro AGA models. In fact the fitting is generally referred to as the 'AGA' fitting. For the rare AGA and Poseidon exceptions we also stock LP regulator hose to second stage swivels that adapt their unique second stage fittings to standard hoses.

In the 90's some regulator manufacturers (notably Apeks, Aqualung, and Mares) started offering some versions of their first stages with an oversized 1/2" low-pressure port. The oversized port has an optimized gas flow path and should be used to supply the primary second stage. (Mares calls it a DFC port.) While the oversized and optimized port does slightly improve machine test results in simulations, most divers found it does nothing significant for actual in-water breathing performance and also inconveniently requires a non-standard regulator hose.

Today, most manufacturers have deprecated their oversized port on first stages for the recreational market, although it continues to be available on versions for the military market. If you are seeking a 1/2" regulator hose, instead your best strategy might be to just plug the oversized port and use one of the other standard size low-pressure ports. If you insist on a regulator hose with a native 1/2"-20 UNF fitting, then take a look at these non-standard regulator hoses.

The first stages of modern SCUBA regulators have 7/16-inch female 'High-Pressure Ports' and every analog submersible pressure gauge (SPG) uses a 7/16-inch male fitting that mates with a female swivel fitting on the other end of the HP hose. These fittings are very standardized and are almost certainly compatible with these same fittings on our HP hoses. Some early vintage (perhaps better described as 'antique') first stages have the high-pressure port size same as a 3/8-inch low-pressure port, but these are extremely uncommon (and dangerous.) For these rare exceptions we stock first stage port adapters.

All submersible pressure gauges also use an air spool with two tiny #003 O-rings to connect the male gauge fitting to the swivel connector on the HP hose female fitting. We always recommend replacing the air spool, or at least the O-rings, whenever you replace the HP hose. Almost all gauges use an air spool with a center flange. However, some inexpensive plastic body gauges use an air spool without the flange. If you have a plastic body gauge you will have to reuse the old air spool from the gauge with the new HP hose.

Some dive computers with an integrated digital pressure gauge, use a special proprietary quick disconnect HP hose that allows the computer to disconnect from the hose without using tools. That special hose is only available from a dealer for your dive computer. Most air integrated dive computer versions use a high-pressure quick disconnect adapter that works with a standard HP hose. Just to be clear, we are not talking about instrument console housings that contain an analog SPG, those work with a standard HP hose.

There are no standard lengths for sidemount hose configurations because most experienced sidemount divers carefully optimize their sidemount rig, thus we don't offer sidemount hose "kits". The type of sidemount harness used, type of cylinders, whether the regulator low-pressure ports are fixed or swivel, plus exactly how the tanks are rigged and carried will all affect the lengths needed.

As a starting point we can only offer some observations regarding typical configurations with swivel turret regulators and aluminum 80 cylinders diving our harnesses. Many divers prefer a {60 in | 1.5 m} regulator hose for donation, but some divers still prefer the {84 in | 2.1 m} LP hose. The other side LP hose is typically { 22 in | 56 cm } but some divers find they prefer a different length that depends on how they like to route their hose. The lengths of the inflator hoses are especially sensitive to causing A-framing, but about { 22 in | 56 cm } is typical for BC hoses. High-pressure hoses are typically either { 6 in | 15 cm } or { 9 in | 23 cm } depending on how the SPG is rigged for sidemount but a few divers prefer using a { 24 in | 61 cm } HP hose.

It's probably not the SPG or hose itself that's leaking. All high pressure SCUBA hoses use an air spool with two tiny #003 O-rings to mate the swivel connector on the female hose fitting to the male fitting on the hose or wireless pressure transmitter. If the air spool O-rings are worn, the assembly can also have a slow leak around the swivel. Even when an O-ring has failed completely or the spool is omitted entirely, a tiny flow restriction present in the high pressure port of the regulator and/or the male hose fitting will cause a leak to be much slower than expected. We recommend replacing the air spool, or at least the spool O-rings, whenever replacing the hose. See our video on Leaking SPG Spool Replacement.

We have seen problems caused by the Schrader valve core becoming partially unseated (or not properly seated during initial assembly) inside the female hose fitting; that's corrected by using a Schrader Valve Tool to tighten the core back in place. We've also seen slow leaks resolved by replacing the worn 011 O-ring located inside the barrel of the female hose fitting, although replacing that O-ring in the QD is challenging to do without a QD O-ring insertion tool and most consumers just replace the entire hose.

The short answer is that the white stuff extruding from the body of the new hose is adhesive, and of no concern. The longer answer is that all SCUBA hoses are constructed of several layers of different materials, and then covered in an outer jacket of either rubber or braided polyester that is adhered together with adhesive. With a very freshly manufactured hose exposed to heat during shipping or direct sunlight, a small amount of the adhesive might extrude out of tiny pin holes in a rubber jacket or between the braids of the polyester strands on a flex jacket. It is not a defect or failure in the hose, and does not mean the hose is leaking now or going to leak in the future. The adhesive will wear off naturally or can be washed off if you wish, and is of no consequence or concern. Regardless, the best practice for dive equipment care is to avoid prolonged exposure to direct sunlight, as the heat and UV from strong sunlight can shorten equipment service life.

Measure the hose from outside end of the female fitting to the o-ring at the base of the male end (i.e. the threads on the male end are not included.) A variation of ± {0.5 in | 13 mm} is allowed on an un-pressurized hose and keep in mind that when pressurized, hoses will change in length anywhere from 2% longer to 4% shorter.

Yes, but it is not practical for us to supply custom length SCUBA hoses in small quantities. Our hose manufacturers typically have a minimum order quantity (MOQ) of at least 100 hoses in any custom length. If the MOQ requirement is not an obstacle, please contact us to discuss your needs.

In many cases an alternative solution is to use a hose repair kit to shorten an existing low-pressure hose. See Hose Repair Kits for more information.

The Alert Diver article titled Air Hoses: A Closer Look has triggered some inquiries regarding material used in the construction of our double braided flex hoses. We've reached out to all our hose suppliers and they assure us we are not receiving any hose constructed with an inner lining of Polyester-based Thermoplastic Polyurethane (TPU) that cause failure of the hose in hot and humid conditions. Regardless, all hose materials have a finite life time and best practice is replace all scuba hoses with over five years of service or 500 dives.

Many original equipment manufacturers of hoses suggest replacing all SCUBA hoses every five years of service or 500 dives, whichever comes first. Keep in mind that all hoses will fail sooner or later either due to age, storage conditions or handling. Scuba hoses, regardless of brand and materials, require some minimal care. Do not allow hoses to receive prolonged exposure sunlight, as the heat and UV from strong sunlight will significantly shorten the life of the hose. Do not attempt to flush the inside of the hose with any form of solvent or other chemical, new hoses are factory clean and if you have any reason to think they are no longer clean then the hose should be replaced. Prior to every dive trip you should always pressurize and inspect your hoses for mechanical damage, corroded fittings, bulges and leaks.

Yes and no; this simple question has a complex answer because there is no widely recognized scuba diving standard for what constitutes suitability for oxygen service. Hypothetically, the equipment we sell could be used with oxygen if we describe it as Nitrox Ready, otherwise you should assume air only service. However, from the point of view of stringent U.S. aerospace guidelines and Compressed Gas Association handling standards for oxygen, nothing in general use in recreational diving is suitable for oxygen service. Using oxygen for diving requires you to make an informed decision to accept for yourself the risks of handing the oxygen. To help form your opinion about the answer read our article About Oxygen Disclaimers.

According to our suppliers, their Nitrox Ready products are oxygen compatible and oxygen clean from the factory, prior to initial use, for compressed gases greater than 23.5% oxygen. (Air is defined as containing from 19% to 23.5% oxygen.) However, most suppliers in the dive industry specify their Nitrox Ready products for use with gas mixtures containing a maximum of 40% oxygen as the upper limit. Although controversial, some dive industry professionals are of the opinion that Nitrox Ready products do not have to be dedicated to oxygen service and may be used interchangeably with CGA Grade "E" air as long as the Nitrox Ready product never contacts gas mixtures in excess of 40% oxygen.

To better understand the issues associated with handling oxygen rich compressed gas, please read Understanding Nitrox Ready.

The 40% specification has become widely used in the recreational diving industry to reduce risk to safety of the diver and limit manufacturer liability, yet indicate a product is (at least initially) oxygen compatible and oxygen clean. For more information please read About Oxygen Disclaimers.

Since Air is defined by the CGA as containing 19% to 23.5% oxygen, describing nitrogen-oxygen gas mixtures up to 23.5% as Nitrox is just an obscure way of describing ordinary Air. Gas mixtures greater than 23.5% oxygen are what most people assume to be Nitrox, and of course there is also pure Oxygen. To avoid conflict with various dive supplier labeling and any misunderstanding about exactly what constitutes Nitrox, Dive Gear Express sometimes uses the phrase "suitable for service with compressed gases containing greater than 23.5% oxygen" to describe products that are both oxygen compatible and oxygen clean prior to initial use, especially in reference to cylinders and valves.

Our suppliers tell us their equipment described as Nitrox Ready is already oxygen clean from the factory. The Compressed Gas Association standards state that equipment handling any Nitrox mixture in excess of 23.5% oxygen shall be cleaned to their standard as if the gas is pure oxygen, there is no lesser standard. That requirement is why Nitrox Ready equipment has already been oxygen cleaned by the manufacturer. SCUBA equipment is labeled 'NITROX READY' or '40% MAX OXYGEN' instead of 'Oxygen Service' because the manufacturers are managing the risks, both to your safety and their liability, associated with oxygen-related fires and explosions by specifying their SCUBA products for use only with breathing gas mixtures no more than 40% oxygen.

Nitrox Ready and Oxygen Service equipment from our suppliers is not just 'kinda sorta clean' or 'premix clean', it is oxygen clean. The practice by shops and individuals of aftermarket cleaning for new dive equipment that is already oxygen clean from the factory is pointless at best and dangerous if done improperly. Prior to initial use, no amount of aftermarket cleaning can make a Nitrox Ready product more oxygen clean nor can cleaning it ever override the manufacturer specified limits. The manufacturer can't stop you from using their equipment with breathing gases and pressures that exceed their specifications, but doing that requires you to make an informed decision to accept for yourself the risks of handing the oxygen.

There is no reliable visual inspection method to determine O-ring material composition, only specialized materials testing equipment can make that determination. Acrylonitrile butadiene rubber elastomers (aka NBR, aka Nitrile, aka Buna-N) are considered to have good resistance to oxygen with a 15 year shelf life. Fluorocarbon elastomers (aka FKM, aka FPM, aka Viton) are considered to have excellent resistance to oxygen, with an essentially unlimited shelf life. To ensure specific composition, O-ring material must be specified at time of purchase and then segregated from other O-rings.

There are no O-ring color coding standards and thus color or appearance is not an indication of the material or quality. O-rings are available in nearly any color, although most commonly seen in black regardless of material. Even though most fluorocarbon O-rings are black, the loose FKM O-rings sold by Dive Gear Express are oxygen compatible and usually brown or green; simply to make them easily distinguishable from more common NBR O-rings which are usually black. However, O-rings inside equipment (valves, regulators, hoses, service kits, etc.) are almost always black regardless of material. O-ring materials also can not be distinguished from each other by their surface appearance, more a function of the manufacturer than the material. NBR is incorrectly said to have a shiny surface and FKM a matte surface. This is not a reliable indicator, and certainly not true if the O-ring has been lubricated.

Just to be clear, the COLOR and SURFACE APPEARANCE of the O-ring is MEANINGLESS regarding their compatibility with oxygen.

Yes. Many divers are surprised to learn the SCUBA industry convention of using fluorocarbon elastomers (FKM or FPM, aka Viton o-rings) with Nitrox is not a matter of oxygen fire safety. The introduction of Nitrox in recreational diving included a recommendation to use FKM for seals in gas blending equipment whose wetted surfaces contact pure Oxygen. This was frequently confused with the very important safety requirement for oxygen cleanliness (i.e. the absence of readily combustible materials); creating a mistaken but widely held belief that Viton is also somehow related to safety of Nitrox for diving equipment such as SCUBA regulators and cylinder valves.

FKM is no more 'safe' in Nitrox diving applications than ordinary synthetic nitrile rubber (NBR aka Buna-N). While FKM has a slightly higher temperature of ignition at {~ 900°F | 500°C} than NBR at {~ 750°F | 400°C}, nearly any material can still serve as fuel in the kindling chain to an oxygen fire that will reach {~ 5000°F | 2700°C}. The reason for preferring FKM in high oxygen content applications is because the service life is typically longer than NBR, i.e. Viton is more resistant to oxidation than nitrile rubber although FKM also exhibits a tendency to swell slightly in high-pressure oxygen. While FKM o-rings theoretically outperform NBR o-rings, in practice there is no safety reason to prefer them in Nitrox SCUBA life-support applications such as regulators and valves given the periodic service requirements of such equipment.

Regardless, Dive Gear Express specifies oxygen compatible and oxygen clean products whenever possible, and we only use viton O-rings and O2 compatible lubricants in equipment service. Any products we identify as Nitrox Ready or Oxygen Service will meet industry standards for both oxygen compatibility and oxygen cleanliness prior to initial use.

The short answer is NO. The longer answer is it depends on the exact product formulation and gas pressure but as a practical matter the answer is still no. Silicone "grease" is a generic term for a variety of lubricant formulations that are based on some form of pure silicone oil, most commonly polydimethylsiloxane (PDMS). While pure PDMS itself is a chemically inert inorganic substance that is not combustible; in order to make the little tub or spray can of generic 'scuba lube', the PDMS is mixed with thickeners and/or organic solvents that typically are readily combustible. Lubricant contamination in high pressure compressed gas equipment is a frequent cause of oxygen fires. In general, lubrication in oxygen service applications should be avoided whenever possible. Oxygen service applications in SCUBA that require lubrication must use specialized (and relatively expensive) lubricants, typically based on polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE) compounds.

It is true that in low pressure Nitrox applications such as regulator second stages and rebreather loops, the type of lubricant is pretty much irrelevant to oxygen fire safety. Occasionally, the desire to minimize use of expensive oxygen compatible lubricants can lead to the erroneous assumption that inexpensive silicone lubricants might used in ambient or low pressure applications that are in close proximity to high pressure applications. However, the high tack and adhesion property of silicone lubes also makes them very migratory and difficult to completely remove. In practice, we find silicone lubrication on the low pressure side of equipment will eventually be transferred to the high pressure side such as a first stage connector or valve outlet. Never use silicone lubricants with electrical contacts, even though this is an often suggested practice. Silicone products will react with plastics and other contaminates to form insulating films and silicone carbide compounds which can cause intermittent connections in low-current applications such as rebreather oxygen sensors. When multiple lubricants are available, there is also the very real increased risk of inadvertently applying the wrong lubricant. In practice, if lubrication is required it is best to only use oxygen compatible lubricant consistently throughout all equipment in service with Nitrox regardless of pressure.

Dive Gear Express avoids silicone lubricants in our facility, using only oxygen compatible lubricants for all SCUBA applications that require lubrication. Any products we identify as Nitrox Ready or Oxygen Service will meet industry standards for both oxygen compatibility and oxygen cleanliness prior to initial use.

DOT regulations currently limit the oxygen fill pressure of aluminum and composite cylinders to 3,000 psi at 70F. There are no similar DOT fill pressure limits for compressed oxygen gas in steel cylinders, but as a practical matter pure oxygen fills exceeding 3,000 psi are highly unlikely, regardless of cylinder composition or service pressure. In the US, almost all bulk compressed oxygen available to local dive shops is aviation grade in steel DOT-3AA-2400 cylinders with a CGA-540 valve at a service pressure of 2,640 psi. Since most oxygen fills by local dive shops are done using the cascade method, a typical local dive shop pure oxygen fill in a rebreather or decompression cylinder will be between 1,800 psi and 2,400 psi unless the shop has an oxygen booster.

The DOT considers any gas containing more than 23.5% oxygen to be pure oxygen for the purposes of handling. Thus, knowledgeable fill station operators will not fill aluminum cylinders with Nitrox higher than 3,000 psi. This means the 3300 psi "compact" or "neutral buoyancy" aluminum SCUBA cylinders will receive a short fill. Again, there are no such restrictions on Nitrox in steel high pressure SCUBA cylinders with a service pressure of 3442 psi. Although there are some older steel SCUBA cylinders with a service pressure of 3500 psi, recent DOT regulations limit the transport of such cylinders to a maximum fill pressure of 3442 psi as well.

We offer two different gas boosters suitable for applications with recreational diving; both are compressed air driven, air cooled, non-lubricated, reciprocating piston, single action single stage type. The DGX Gears X-30 is a value priced oxygen booster that is suitable for light duty usage. The faster Haskel MSB-9000 is a premium quality oxygen booster manufactured in the USA that is suitable for heavy duty usage. A benefit of the Haskel booster is additional cooling provided by routing the cold exhausted drive air through a jacket surrounding the gas compression barrel.

Best practice when boosting oxygen is to keep a low ratio between the source/target pressures and reduce the cycle speed as the ratio increases because rapid compression of oxygen also increases the risk of adiabatic combustion. Dive Gear Express recommends not exceeding a boost ratio of 6:1 when boosting oxygen. It may be tempting to pull the maximum amount of gas out of the supply cylinder, but boosting low pressures can very quickly reach high boost ratios. For example, boosting from a {500 psi | 35 bar} source to a target of {2640 psi | 180 bar} is a relatively low boost ratio of about 5:1. However, a source of {300 psi | 20 bar} almost doubles the ratio to about 9:1 and an only slightly lower source of {150 psi | 10 Bar} doubles again to an 18:1 ratio.