The BC-002 Aquatec Navy military Horse Collar BCD from uses a two-layer bladder design The outer bladder layer is made from tough 1000 denier Cordura, while the Inner bladder layer is made from 0.4mm polyurethane The bladder uses a one cell design so that air cannot be trapped in any part of the bladder This navy horse collar bcd offers excellent front stability 2 overpressure valves, a power inflator, and L/P hose are included.