The exposure usb rcr123 charger uk consists of a usb cable charger and two re chargeable li ion batteries either one or two batteries can be charged at any time this charger pack is used for the spark flash and flare exposure lights the charge time is approximately 4 hours and simply connects to your laptop or desktop computer exposure usb rcr123 charger uk features charges either one or two batteries at the same time used for the spark flash and flare exposure lights