I know that this has been posted a few times before, and I thought they would be all gone but just to say they're still available in some poundlands!
Got mine at the one at Shepard's Bush, London
has dual usb ports to charge two devices, compatible with iphones and basically anything which charges from a usb port.
note: no usb cables included, but for £1 still HOT
Input: 12 to 24 V
Output: 5 V
Max: 1000 mA