Night diving is so awesome. You'll see new marine life behaviours, interactions and often new life all together with the setting of the sun. Of course, night diving brings with it unique challenges like, well, the fact that it's night and therfore dark.
The Scubapro Flashy light is here to help with that problem. It's a robust little underwater light, designed to be used as a marker. You and your buddy could wear one each to help with your buddy skills in the dark waters, you could use one to mark your ascent line, entry point, bits of a wreck - whatever you need to keep track of underwater!
Comes with batteries, and rated to 100m!