Just a word of warning guy's, don't plug them into your laptop or computer to charge them. I've had 3 this month already that have gone bang. One caused a serious fire and another caused a bad laceration to some guys thigh.
I've heard of others exploding (did they actually explode) when they were using it.
I assumed you plugged into the mains via an Apple usb plug or similar. I would have thought the mains is more likely to explode than a laptop/PC.
I have to ask Hovis, if #1 went bang, and #2 went bang would you not question how they were being charged?