The loud 125-125dB resonating frequency generated by the ISC Duo Alert Horn can be heard on the surface for approximately 1 Kilometer (about 6/10th mile) and for about 300 feet underwater.
Type I: fits any standard bcd inflator hose.
Type III: fits Aeris Air Link, Apeks Octo+, Aqualung Air Mic, Aqualung/Seaquest Air Source, Beuchat Venturi, Oceanic Air XS2, Zeagle Octo+.