The O2ptima CM is a chest-mounted, electronically controlled, constant PO₂, fully closed-circuit rebreather (eCCR) designed for the demanding needs of technical divers. With built-in decompression calculation, mixed gas capability, and a rugged, compact form factor, the O2ptima CM is ideal for environments where a direct ascent is not an option—such as caves, wrecks, and deep open-ocean dives.
Key Features (Standard)
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Chest-Mounted Counterlungs
Positioned for optimal trim and work of breathing, the counterlungs provide a total loop volume of 6 liters.
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Redundant Shearwater DiveCAN Electronics
Includes a primary Petrel 3 controller and a heads-up display (HUD).
(Optional: upgrade to a NERD 2 controller for hands-free visibility.)
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Dual-Use Scrubber Canister
Compatible with both Micropore ExtendAir® cartridges and loose-fill CO₂ absorbent, allowing user preference or mission-specific flexibility.
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Dive Rite DSV (Dive Surface Valve)
Durable, easy-to-service DSV comes standard for dependable loop control and surface breathing.
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Dual Water Traps
Integrated into both the counterlungs and scrubber lid to prevent moisture ingress and protect the scrubber bed from contamination.
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Oxygen Delivery System
Includes oxygen regulator, high-pressure hoses, and manifold plumbing tailored for CCR diving.
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(4) AI R22 Oxygen Sensors
High-precision sensors for accurate and redundant PO₂ monitoring in a critical life-support system.
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Durable Outer Shell
Encased in a Superfabric®-reinforced cover, offering exceptional abrasion resistance and field durability in tight environments.
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Oxygen Cylinder (Optional)
Comes with an AL13 oxygen cylinder and DIN valve, suitable for most cave and technical profiles.
Technical Highlights
• Type: Fully Closed Circuit Rebreather (eCCR)
• Control System: Constant PO₂, electronically regulated
• Mounting: Chest-mount design for optimized trim
• Scrubber Type: Horizontal, dual-mode (ExtendAir® or loose-fill)
• Loop Volume: 6 liters
• Electronics: Shearwater DiveCAN (Petrel 3 + HUD standard)
• PO₂ Sensors: 4 × AI R22
• Construction: Rugged, low-profile design with abrasion-resistant materials
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Gas Flow Path
The O2ptima CM’s loop is designed for intuitive, directional gas flow:
From the diver, exhaled gas passes through the DSV and enters the right (exhalation) counterlung.
The gas then travels through the scrubber canister, where CO₂ is removed via Micropore ExtendAir® cartridge or loose-fill absorbent.
After scrubbing, the clean gas flows into the left (inhalation) counterlung.
From the left counterlung, the gas is inhaled back to the diver via the breathing hose.
This right-to-left loop orientation supports an efficient cycle with minimal resistance, enhancing both comfort and safety over long-duration dives.
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(Click on Image to Enlarge)
A
Dive/Surface Valve
The Dive/Surface Valve (DSV) has been redesigned from the ground up for exceptionally low work of breathing in a compact and streamlined form. Its engineering prioritizes both performance and ease of maintenance, making it ideal for demanding rebreather applications.
B
Exhalation Loop Hose
C
Exhalation Counterlung
D
Oxygen Manual Addition Valve (MAV)
The oxygen manual addition valve is a dry-suit style, side-push valve. It uses a standard LP inflator hose connector. This valve allows for the manual addition of oxygen and supports both on-board and off-board gas supplies.
E
Overpressure / Dump Valve (OPV)
The O2ptima CM features a dedicated loop overpressure valve (OPV) mounted on the exhalation (right) counterlung. It utilizes a specially selected spring designed to provide optimal cracking pressure specifically for rebreather counterlung performance.
F
Scrubber End Cap and Water Trap
The scrubber end cap features a snap-in, cone-shaped water trap designed to prevent excess water from entering the scrubber canister, regardless of the diver’s orientation in the water.
G
Scrubber Canister
The scrubber canister holds the scrubbing media responsible for removing CO2 from the breathing loop. The O2ptima CM utilizes an axial-style scrubber canister, compatible with both Micropore ExtendAir cartridges and loose, packable CO2 absorbent.
H
Oxygen Sensors
The O2ptima CM utilizes four oxygen sensors, which are threaded into the sensor disk located within the electronics head. Dive Rite specifies the use of Analytical Industries, Inc. type R22D sensors for this configuration.
I
Electronics Head
The electronics head houses the solenoid, four oxygen sensors, sensor disk, sensor wiring harness, and the oxygen injection premix tube. Together, these components monitor the oxygen content within the breathing loop and control oxygen injection to maintain the desired setpoint.
J
Inhalation Counterlung
K
ADV/MAV
The ADV/MAV mounts to the inhalation counterlung and activates automatically via negative loop pressure or manually by pressing the diaphragm, similar to a second-stage regulator.
L
Inhalation Loop Hose
M
Electronics / Battery Canisters
The O2ptima CM features two external electronics and battery canisters, mounted in elastic sleeves between the scrubber canister and the counterlungs at the base of the outer bag.
One canister houses the SOLO (Solenoid and Oxygen) electronics board and its power source—a standard 9-volt battery. This battery supplies power to both the SOLO board and the oxygen solenoid. The Petrel 3 controller handset operates independently, using its own internal battery.
The second canister contains the OBOE (Oxygen Board Electronics) board and a standard AA battery. This battery powers only the OBOE board and the heads-up display (HUD).
N
Controller
Dive Rite has selected Shearwater electronics for control and monitoring of the O2ptima CM. The system is operated using a DiveCAN Petrel 3 handset, which provides diver-adjustable PPO₂ setpoint control and real-time monitoring of oxygen sensors 1, 2, and 3C. In addition to loop control, the Petrel 3 functions as a full-featured dive computer, displaying depth, dive time, decompression status, and other critical dive parameters.
O
HUD
The O2ptima CM is equipped with a Shearwater Heads-Up Display (HUD) that provides real-time PPO₂ readings from oxygen sensors 1, 2, and 3H. These readings are shown using three vertical columns of LEDs, with each column corresponding to an individual sensor. The LEDs flash in a modified Smither’s code to indicate PPO₂ levels, and a “color blind” mode is available for enhanced accessibility.
The HUD can be configured for either right or left eye use. It can be manually activated by pressing the button on the end of the housing. Additionally, integrated wet contacts automatically power on the HUD if it was not manually turned on before entering the water.
P
Regulator, Hoses, and Guages
A Dive Rite first stage regulator with a DIN connector and hose assembly is included for the oxygen supply. The intermediate pressure (IP) is factory-set to 85 psi to match the requirements of the oxygen system. It is critical that the oxygen regulator IP does not exceed 85 psi, as this is the maximum rated pressure for the solenoid.
TECHNICAL SPECIFICATIONS
Weight: 14 lbs 6 oz (6.5 kg) without cylinders or scrubber media
Oxygen 1st Stage Intermediate Pressure: 85 psi
Batteries: Petrel 3 Controller (Internal): AA
Counterlung Volume | 6 Liter Total Loop Volume |
Maximum Operational Depth | Max Depth 40 m (130 fsw) with Air diluent. Max Depth 100 m (330 fsw) with Trimix diluent
Operating Temperatures | +39°F to +90°F (+4°C to +32°C) |
Short-Term (hours) Temperature Range| -4°F to +122°F (-20°C to +50°C) |
Long-Term Storage Temperature Range | +41°F to +68°F (+5°C to +20°C) |
Oxygen Sensors | Analytical Industries, Inc. type R22D sensors (x4)
Oxygen Sensor Operational Voltages | 8 – 14 mV in air @ sea level. 40 – 65 mV in pure oxygen @ sea level |
Oxygen PPO₂ Setpoint Range | 0.5 – 1.5 PPO₂ during dive mode
(0.19 PPO₂ available in surface mode only) |
Water Traps | 2 water traps—one in the scrubber lid and one in the exhaust counterlung bladder |
