DiveAlert DB1 Air Horn Surface Signalling Device DiveAlert is a specially designed, small, light weight air horn that uses quick-connect / disconnect hose couplings to become an integrated part of your power inflator and buoyancy compensator. Installation is easy and only takes a moment. DiveAlert uses a small amount of air from your SCUBA tank to make a piercingly loud sound. People have been able to hear a DiveAlert one mile away from a diver in need. In conditions where visibility is limited, a DiveAlert can be a life saver.  Features: Standard Fitting: DB1 Fits All Standard Inflators hoses, including the Aqualung i3 Control System No Mods Required: DiveAlert does not require any modification to your equipment, and it does not interfere with the normal operation of your equipment. Easy To Use Design: Simply press the red button to create a piercingly loud sound. Do not point the DiveAlert towards anyone, as it could cause hearing damage. It is that loud. How It Works:  The DiveAlert uses chrome-plated brass couplings to attach to your power inflator. The activator button engages a chrome-plated brass actuator valve stem causing a small amount of air to rush by a stainless steel diaphragm, emitting a piercingly loud sound from the injection-molded thermoplastic body. Maintenance: After each use, the DiveAlert should be soaked with warm fresh water. This is especially important after use in chlorinated swimming pools and in other water having corrosive substances. Additionally, it is highly recommended that you blow the water out of DiveAlert before storing. This can be done by pressurizing and pushing the button. (We recommend that you cup your hand over the surface horn to muffle the loud noise. What to do if your DiveAlert is just blowing air - no sound If your DiveAlert is not screaming with the obnoxious 130 dB blast you\' have come to know and love, here is a quick video to possibly solve that issue. Test for sound after this process.