Guillaume Nery is a three-time free dive world record holder and brand ambassador to Ball Watch Company. He makes dives without assistance or equipment on a regular basis to depths of 100 meters (330 feet). This is not only hard to do, it is hard to see while doing it. The ambient light is about 1% of surface light at these depths. This is where the 53 micro gas tubes (tritium) come in very handy and why he uses the EMII Diver GMT watch. The watch has a rotating inner bezel the utilizes 41 of the gas tubes with the remaining 12 being placed on the hands and dial. This illumination setup is very beneficial and allows divers to see their watch at any depth.