So you want to invent or produce an item that a diver may or may not need.? How about an affordable but effectie boat diving safety kit. It would comprise of a watertight tube or container capable of staying dry at or slightly beyond recreational limits. it would contain a whistle, signal mirror, compact flares, marker dye, surface marker (long bright plastic strip that increases visibilty for search planes), and a strobe light. you could make it with a little extra room for someone who wants to customize it a little. The kit should be designed to be portable and compatible with standard jacket and back inflate BC’s (maybe two or three methods of attachment). Very few recreational divers ever think twice about what they need when they jump in offshore. Especially with private boats. I have spoken with a diver who lost his boat due to a drifting anchor syndrome. the guys in the baot didnt know they were drifting. the baot was over 2 miles away when they finally made the ascent. having signalling equipment would have made a difference in how long they were adrift. anyway, thats my advice.