The Hellephone is a single-sideband (SSB) wireless underwater telephone that provides clear reliable diver to diver, diver to surface and surface to diver communication. The system operates like a portable two-way radio but uses acoustic signals instead of radio waves. Any number of divers and surface personnel can converse in the same area at the same time.

Hellephone allows divers to stay in contact with each other regardless of visual conditions, and avoids the need for sometimes awkward or misunderstood hand signals. This is particularly important when diving on wrecks, on engineering jobs or in other awkward locations, and considerably enhances safety in such situations.

The Hellephone system allows divers to change dive plans together, avoid hazards by verbal warnings and quickly deal with any emergencies that do occur by calling immediately for assistance or directing in the aid.

For the sport divers Hellephones considerably enhance the enjoyment of the underwater world by allowing easy communication about interesting points in the environment, making the dive more of a shared experience. For the commercial diver the Nautronix system provides an invaluable aid to increase both safety and efficiency.

The system consists of the Model 3145B Diver Unit and the Model 3151 Surface Unit. Both units are lightweight and compact and feature on/off volume control, voice operated transmit (VOX) control, squelch control and a low battery indicator. On the model 3145B Diver Unit, the controls are all adjustable by the diver during the dive, providing increased flexibility and safety in the system.