This unit is designed exclusively for DIVERS. It withstands depths of up to 100 meters, has a 1 meter long high visibility electro-luninescent light cord that flashes SOS, and activates manually. It is available with a compact neoprene pouch and brass bolt snap that enables the diver to easily clip the unit onto the dive kit. In addition to dive boats equipped with the Sea Marshall's on-board Diver Locating System, any emergency vessel in the area (i.e. Coast Guard, Police boats, military, airplanes, etc) will be able to hone in on the signal.