Hi... I have taken OW certification course twice, and I have taken Red Cross CPR (Professional Rescuer/1st Responder) seven times. And nobody ever told me that there are CPR masks and shields designed especially for divers! These devices are the same as the "normal" ones, but lack the bio filter, which clogs when wet! Needless to say, I have one in my gear bag now. I just though someone else might appreciate the info. Look at http://www.cpr-pro.com/divers.html
Andy
Andy