Dive Rite Modular Valve System offers 200-Bar and 300-Bar valve and manifold designs. The advantage of the modular valves are that they may be connected using a manifold to construct a set of doubles, or connected together to form what is known as an H-valve for use on a single cylinder. The manifolded doubles are sometimes disassembled, the manifold removed, and the left-hand and right-hand modular valve manifold ports are plugged to make two single cylinders. Left and right modular valves are also commonly found in the pairs of single cylinders used with fully closed-circuit rebreathers.

All Dive Rite manifolds and valves come standard with burst disks for service pressures up to 3500 psi. All Dive Rite manifolds and valves come with Viton o-rings and oxygen compatible lubricants and are Nitrox Ready.

Dive Gear Express offers diving products labeled Nitrox Ready, whose oxygen-compatible components are free of hydrocarbons and other contaminants. With Dive Gear Express, you don't have to make expensive aftermarket alterations to use oxygen-rich gas mixtures.

to read What Does Nitrox-Ready Mean?

Do You Know Your Right From Your Left?

Modular valves come in right-hand and left-hand designs, referring to the side of the valve handwheel, not to which direction the valve opens. This can be confusing because there is not industry-wide agreement on the perspective from which the valve is viewed.

• Dive Rite assigns left and right from the perspective with your face toward the valve opening. Thus Dive Rite says that the typical standalone valve is left-handed.

• Thermo assigns left and right from the perspective with your face away from the valve opening (i.e., the tank is on your back). Thus Thermo says that the typical standalone valve is right-handed.

While both right- and left-hand valves always close and open using the "righty-tighty, lefty-loosey" rule, this can cause problems when modular valves are mounted on single tanks. Well-meaning individuals who fail to notice a valve with the handwheel on the uncommon side and reach to check "air is on" might actually close a valve believing they are doing the diver a favor of opening it. To prevent this from happening, it's a good idea to call modular valve configurations to the attention of divemasters and buddies.