Powerall

Got one of these the other month, used to use jump packs and jumper leads but one look at this, brilliant.

Started a couple of cars and a bike already without charging, will apparently do about 20 starts on one charge and will be a good back up on the road king for trips away, small to pack and will also charge my cell phone from USB

165mm X 73mm just a bit bigger than a cell phone!

http://www.thepowerall.com/

highly recommend