For my 32nd birthday my wife gifted me a Light and Motion SOLA 500 SCUBA light. You really can’t go wrong with having more than enough lights underwater especially when the sun sets. Well that’s one use: in my current UW photography setup I have two YS-110a strobes that also have limited use asa real underwater flashlight. However, I was advised that keeping it on for long periods (i.e. more 5 minutes) might destroy the bulb as its main purpose is really a strobe / flash.