You got a D8 Light and are getting ready to take a once in a lifetime dive vacation to some exotic remote location and have been told how much night diving you are going to have available. The problem is you just realized you don't have rechargeable batteries for your light. Carrying 16 to 24 spare D-Size batteries can sure cost a lot in excess baggage fees. Well get this charger and neverworry again. Your battery problem is solved.