Princeton Tec Shockwave II Light Great Scuba Gear - Power up from 7.5 watts to 15 watts of power with the flip of a switch. The economical 7.5 watt output mode burns for up to 10 hours and provides plenty of light for most diving conditions. For those really dark nights, wreck diving and deep, dark crevices, simply flip the switch to the screaming bright 15-watt output mode.