The CHest Mounted O2ptima


Unmatched Versatility...

The most versatile tool for underwater exploration.

The simplicity of the O2ptima CM results in pretty much limitless possibilities of use. The O2ptima CM, aka Choptima, is fully compatible with whatever open-circuit system you’re currently diving: sidemount, back mounted doubles, or even a single tank. The chest mounted design easily attaches to almost any harness using four bolt snaps which means you can most likely keep diving your current dive kit. The CM Optima rebreather can be quickly added or removed for any mission. Add it to your single tank rig for a deep ocean dive and remove it later for a shallow open circuit reef dive if you so desire or just continue to enjoy the freedom and silence of the rebreather. Use it in place of a stage bottle to greatly extend your penetration distance in an overhead environment. Remove and stage it underwater for later decompression or to navigate tight restrictions… 

The possibilities are truly endless and the O2ptima CM has been used for cutting edge exploration and world class expeditions all over the globe. It has been dove in some of the most extreme conditions; the frozen caves of Norway, massive caves and sumps in Mexico and the Carribean and soon to the deep ocean wreck of the Britannic. Rest assured the Dive Rite Chest Mount O2ptima can take you where you want to go! 

The design parameters for the O2ptima CM were simple and included:

  • Keep the breathing loop as short as possible.
  • Use state-of-the-art electronics from Shearwater Research
  • Be fully compatible with the ExtendAir CO2 Absorbent Cartridge.

All of these parameters were achieved in a rugged and durable package with the smallest profile possible.

Dive Rite has committed to ensuring that it is one of the most reliable, capable, and high performing rebreathers on the market. The O2ptima design continues to evolve as units are tested, refinements are made, and new technology becomes available. We are certain that this unit will provide you with many unforgettable hours exploring your underwater world.

The O2ptima CM breathing loop is one of the shortest of any rebreather on the market. 12 inch (30 cm) loop hoses come standard with 10 inch (25 cm) hoses available for an improved fit on smaller divers. The hose diameter and lengths have been specifically chosen to provide the best balance of comfort and low work of breathing. The hoses are easy to replace with two specially sized worm clamps holding them onto the DSV flanges.

The hoses are lined with an antimicrobial coating to help keep bacteria from growing in the loop after repetitive dives in extreme conditions.

The O2ptima CM uses two integrated, chest mounted counterlungs with 6.4 liters of total loop volume. This choice of position keeps them as close as possible to the diver’s lung centroid. This design provides for incredibly low work of breathing in a variety of diver orientations. There is an internal water trap located at the bottom of the exhalation counterlung, which makes dewatering the loop easy.

We have never personally felt easier work of breathing in any CCR. Our team of instructors can make sure they unit is best setup for your body type to make sure you get to experience the same incredible work of breathing. 

The outer bag of the counterlung contains a zippered storage pouch on the front for stowing accessories.  and most importantly decompression snacks and beverages for those long technical dives. 

It also features a Dive Rite line cutter with ceramic blade, for those of you who don’t rinse gear, attached to the chest with a velcro closure to make sure you always have a cutting tool at hand. 

The O2ptima CM comes standard with a Dive Rite DSV. This DSV has been completely redesigned from the ground up so that it has an exceptionally low work of breathing in the most compact design possible. Two high performance mushroom valves are utilized to ensure one way gas travel.

The Choptima DSV is designed to be user serviceable and is a friction DSV design so there are no o-rings to pinch on the barrel which helps keep maintenance to a minimum. The DSV is serviceable by the diver and we have a video in the CM Resources section that walks you through this process step by step.

Tech Info

  • Proudly made in the USA.
  • Fully electronically controlled closed circuit rebreather (eCCR).
  • Redundant Shearwater DiveCAN electronics including Heads-Up Display (HUD) and Petrel 3 controller or NERD 2 controller.
  • Water traps inside of the counterlungs and the scrubber end cap.
  • Unique scrubber design fully compatible with the ExtendAir CO2 Absorbent Cartridge is also packable with about five pounds (2.2 kg) of granular absorbent.
  • Weight: 14.4 pounds (without oxygen cylinder or scrubber material).
  • SuperFabric® soft cover for abrasion protection.
  • Compact Dive Rite DSV (Dive Surface Valve).
  • Oxygen MAV (Manual Add Valve).
  • Diluent combination ADV/MAV (Automatic Diluent Valve/Manual Add Valve) or MAV only.
  • Dive Rite FT1 first stage oxygen regulator.
  • Four AI R22 oxygen sensors.
  • Compatible with any harness with two high shoulder D-rings and 2 waist D-rings.
  • Compatible Cylinders (not included): AL 13 (recommended), AL 20, AA LP 13