Dive Alert Plus is a specially designed, small, lightweight pneumatic signaling device that uses quick connect hose fittings to become an integrated part of a diver's BCD power inflator. Installation is easy, and does not require any modification of your other equipment. Dive Alert Plus uses a small amount of air from your scuba cylinder to produce a loud sound that's audible both on the surface and underwater. Features: SCUBA air horn signaling device works above or below the surface Quick connector attachment between the power inflator and low pressure hose Squeeze lightly for a subsurface signal, harder above water for a loud surface signal blast Injection molded thermoplastic with stainless steel diaphragms and chrome plated brass couplings Simple, large pushbutton control