The AP Back Mounted Counterlungs (BMCL) were introduced in 2012 as an option for all AP rebreathers as an alternative to the over-the-shoulder counterlungs which have been standard on all AP CCRs since 1997. They can either be fitted as an upgrade to existing AP rebreathers or specified when ordering any new AP unit.

Why Back Mounted Counterlungs?

• Clutter-free chest area
• Stream-lined diver profile with reduced drag
• More space available to clip on and retrieve extra items of kit
• Easy to trim for horizontal attitude
• Unique integral shoulder strap & harness design ensures the counterlung is fixed in the optimum position
• Excellent breathing characteristics in all typical diving positions
• CE Approved

The Back Mounted Counterlung design is the product of many years experience and development involving extensive manned and unmanned trials and testing. Our primary goal was to optimise the work-of-breathing performance of the lung.

As a result, we have now produced a unique back-mounted counterlung - the best available and comparable to the renowned high performance of our existing over-the-shoulder design.

The BMCL offers excellent breathing characteristics in all typical diving positions. Only lying on your back does the breathing effort become slightly more noticeable.

The BMCL consists of 5 main components:

• Counterlung – 2 sizes
• Harness – 5 sizes - Small to XXL
• Diluent Inflator and Hose (3 hose sizes)
• Oxygen Inflator and Hose (3 hose sizes)
• Auto Diluent Valve - ADV
• Oxygen Inflator Is Not Included In This Configuration. Please click this link to purchase.

Please specify your options below.

Counterlung Colour

Colour options: Black with Yellow or Grey trim

Counterlung Size

Two sizes available - Small and Standard. They both have the same lung volume but the Small is designed for narrower shoulders and a shorter back and is designed for use with the Small BMCL harness - see guide below.

Harness Size

Five sizes available - see guide below.

The harness features AP rebreather weight pockets, multiple stainless D rings, thru-the-legs crotch straps and a comfort pad.

Manual Inflator Options

Please Note: The Oxygen and Diluent inflator assemblies are optional, according to your training level or configuration preferences. However, customers should ensure that they have at least one means of adding diluent gas, either an ADV or diluent inflator or preferably both. Please see the Manual Inflator Hose size guide below and specify the hose length you require.

ADV - Auto Diluent Valve

The ADV is optional but we strongly advise that the BMC performs best with an ADV fitted.

Shoulder Strap Comfort Pads (pair)

Designed to provide padding for the collar bone area. The comfort pads thread onto the shoulder straps and can be fitted to all 5 harness sizes.

Scooter Strap

An alternative to the double thru-the-legs crotch strap (included as standard) the Scooter Strap is a single 50mm webbing crotch strap with stainless steel 3-bar sliders and a stainless stand-off D ring for attaching kit.

The position of this D ring is adjustable along the webbing and can be located front, back or somewhere in-between. It is ideal for scooter attachment.

Configuration Guides - click below:

• Counterlung Size Guide 
• Harness Sizing
• Auto Diluent Valve
• Inflator Hose Size Guide 
• Shoulder Pads & Scooter Straps