Computers

The Descent X30 is compact and affordable - perfect for recreational and open-circuit technical divers. The Descent X50i is designed for technical divers requiring rebreather support, diver-to-diver communication, and deeper dive limits. The X50i together with the T2 wireless transceiver also supports tank pressure reporting and in-water communication via preformatted messages with other networked divers wearing their Descent™ Mk3i or X50i dive computers.

VPM-B remains a legacy model associated with older deep-stop bubble-model practice; recent decompression research and expert guidance have increasingly questioned the benefit of deep-stop profiles, and commercial-algorithm validation work found that Bühlmann GF can be tuned to pass proposed validation tests whereas VPM-B could not be tuned to address its too-deep first-stop behavior. For those reasons, VPM-B is without a clear evidence-based benefit for most Shearwater customers.

Shearwater has chosen Bühlmann ZHL-16C with Gradient Factors for newer models such as the Perdix 3, which does not offer VPM-B. Following the direction Shearwater has chosen, Dive Gear Express has elected to no longer offer VPM-B as an option, even where it remains available on earlier models. Gradient Factors let divers adjust first-stop behavior and shallow-stop conservatism within a transparent, widely supported decompression model.

VPM-B is associated with older deep-stop bubble-model practice. Decompression research has challenged the benefit of those profiles, and validation studies have identified problems with excessively deep initial stops.

If you are screwing the transmitter directly into a first stage HP port (or a HP stand off adapter or HP pivot swivel that are simply extending the port) then the Apeks, Mares, and Shearwater transmitters do not require an air-spool. However, the Garmin, Halcyon, and Suunto transmitters require inserting the flow-restrictor that was included with the transmitter and then screwing the assembly in to the HP port (or standoff, or pivot swivel.) Finally, snug up the transmitter with a thin wrench, but do not overtighten... the O-ring at the base of the threads on the transmitter is what makes the seal.

If the transmitter will be attached to the swivel end of a high-pressure hose then you will need use an air-spool. The Garmin and Sunnto transmitters require special unique air-spools that include flow restrictors (different from their flow restrictors used with first stage ports) that must be used in place of a standard air spool. The Apeks, Mares, Halcyon, and Shearwater transmitters do not include an air-spool and you will need to supply a standard air-spool you purchased separately with the HP hose. In this case the standard air-spool may be inserted into the transmitter and then screwed in to the hose swivel and snugged up with a wrench. Take care not to nick the o-rings during assembly; a few people also prefer to add a very small amount of oxygen-compatible lubricant to the o-rings. Regardless, when the transmitter is snugged up to the hose swivel, the transmitter may (or may not) turn freely (or at all) on the end of the hose.

Shearwater offers a wide array of computer models tailored to the requirements of different styles of diving and the preferences of different divers. They publish this Shearwater Dive Computer Comparison chart PDF that compares and contrasts the differences in features and functionality.

Open circuit sport and advanced nitrox divers should consider the Peregrine and Tern models. Technical divers needing full mixed gas and/or closed-circuit capabilities should consider the Teric and Perdix models. The Petrel is Shearwater's most feature rich expedition grade model with the largest display. AMOLED displays are the most readable underwater, while Backlit LCD displays offer the best value. The NERD is a unique heads-up display model often seen in rebreather applications.

For the current models, see our Perdix 3 vs Petrel 3 comparison, including housing, display, battery, and rebreather connection differences.

The original Shearwater Peregrine was announced in July 2020. In May 2023, Shearwater announced the Adventures Edition Peregrine in both "Light" and "Dark" versions that differ only in cosmetic styling from the "Original" edition. In May 2024, Shearwater introduced the "TX" edition of the Peregrine which supports integration with the SWIFT tank pressure transmitter, also called wireless 'air integration' (AI) and also includes an electronic compass. While the TX edition does support AI and compass, the earlier lower priced editions do NOT and can not be later upgraded.

Symbios “Blue” is identical to the Symbios "Silver" version with the single exception that it does not include handset integration for Halcyon rebreathers. It does include a fixed PO2 setpoint mode for non-integrated rebreather diving. The Blue version offers compatibility with the wider Symbios wireless ecosystem, including the Symbios Tank Pod (aka AI tank-pressure transmitter), DPV interface, and GPS Pod. Unless you foresee diving with a Halcyon brand rebreather, the Blue version represents a better value.

The Shearwater dive computers sold by Dive Gear Express support English by default and also include language support for: Chinese-Simplified, Chinese-Traditional, French, German, Italian, Japanese, Polish, Portuguese, and Spanish.

The Garmin dive computers sold by Dive Gear Express support English by default and include a language pack that also supports: Български (Bulgaria), Čeština (Czech), Dansk (Danish), Deutsch (German), Eesti (Estonian), Eλληνικά (Greek), Español (Spanish), Français (French), Hrvatski (Croatian), Italiano (Italian), Latviešu (Latvian), Lietuvių (Lithuanian), Magyar(Hungarian), Nederlands (Netherlands), Norsk (Norwegian), Polski (Polish), Português (Portuguese), Русский (Russian - East Slavic), Română (Romanian), Slovenčina (West Slavic), Slovenščina (South Slavic), Suomi (Finnish), Svenska (Swedish), Türkçe (Turkish), and Yĸpaïaϲbĸa (Ukrainian).

All Garmin watches always support English, but have two different firmware versions that in turn each supports a specific language pack software download. The firmware version of the watch depends on the country of the authorized retailer: Asian Pacific (APAC) that supports the CJK ideographic character sets OR Rest of the World (RoW). The firmware between the APAC and RoW versions is different, so changing the language is not just a matter of downloading a different language pack. The Descent models sold by Dive Gear Express are the RoW version, not the APAC version, and do not support Chinese, Japanese or Korean languages.

The short answer is you do NOT need the upgrade.

VPM and DCIEM are additional decompression models available on some Shearwater dive computers as an optional alternative to the default Bühlmann GF gas content model used by all Shearwater dive computers (and most other dive computers) to compute no-decompression limits and decompression schedules for dives. For recreational diving, there is no expert consensus that VPM or DCIEM is better than Bühlmann. If you don't understand the differences and why you would choose one or the other, Dive Gear Express and Shearwater recommends sticking with the factory default of Bühlmann 30/70.

Avelo Mode allows a Recreational Avelo Diver using the Avelo Dive System equipment to gain easy visibility of their Avelo dive data and ensure accurate gas time remaining on the Teric dive computer when also paired with a SWIFT transmitter.