By placing the Front-Mounted Counterlungs (FMCL) close to your lungs, you can experience a low work of breathing. The Over-Pressure Valve (OPV), which is easily accessible, allows for effective loop control. This FMCL set comes with various features such as removable inner bladders, 2 x D-rings and straps that keep the counterlungs tight along with an inflator holder and velcro patch for personalization. Volume 6.2 liters. Pair with the 6011-074 MAV Pack for Loop Injection to add manual addition valves.