Typically if divers want to talk to each other they have to wear special face masks which are heavy and expensive. The Logosease, though, is affordable and easy to wear, and does not cover the whole face. Simply attach the device to diving mask and it can will be able to talk through the air regulator in a mouth.
The Logosease has a range from 50 to 100 meters (164-328 feet) and can function as far as 40 meters (131 feet) underwater. Of course, voice quality is not going to be as good as when speaking regularly on land but Casio still hails this as a world-first for an instrument of its kind.