Glenn: A more sophisticated system than the GSM is required. I like their full face masks, but I returned the GSM units as being unintelligible. A "real" system runs about $1000 per diver for the comm units.
Glenn F Thx -- I'm now researching what is the best mask for the money...or rather how much I'm going to spend? I'm new to diving, as in just certified, and thought Ocean Reef was the only choice but now I'm learning about others etc. What advice would you give for the best choices - really just looking for the ability to communicate w/ the surface. THX