I usually really like BD gear and have had no problems with it in the past. This item, however, does not match up with BD's usual standard.
I purchased one of these from Black Diamond and it would not hold a charge. I then spoke with their warranty department and was sent a second unit that had the same issue and would not hold a charge either.
I just finished disassembling the first unit, and the rechargeable battery is just 4 NiMH AAAs glued together and wired to some charging hardware in the base. You could buy 8 rechargeable AAAs along with a wall charger for the same price as this unit, which is really just a dressed up set of 4 AAAs with performance issues.
Don't buy this thing. It's a waste of your money.