This charger will only work with single layer battery (such as Stock battery). It will not work with double layer extended battery. If you have a double layer extended battery, which has twice the thickness of the stock battery, this charger is not for you. You do not need a special back cover to use this battery This package is specifically designed for the cellphones we list here, if your cellphone is not in the list , then it's not for you. =============================================================================================== 100% Brand New. 1)Universal USB/AC Charger: * To Charge battery for Samsung Convoy 3 SCH-U680( Verizon ) , allow the 2 metal pins on the charger to touch the 1st and the 3rd contacts of battery. * For other batteries, Please refer to battery user manual to check which pins to be connected, contact points would vary on different batteries. * You might also want to flip over the battery and try different contacts on the battery. * You should see the LED light turn blue on the charger, that means the contacts has been firmly connected. * Now you could plug in the charger with the battery into a power socket. * The LED Light will turn Red when charging the battery, turn blue to indicate the battery is fully charged. * This battery charger comes with an USB outlet which could also be used for various cell phones,as long as the cell phone could be charged thru an USB port. 2)USB Data Sync Charging Cable 3 Feet: * New generic 2 in 1 Data/Charging USB Cable. * Charging your Cell phone by connecting this charging cable to our Wall charger. * Provides data transfer, syncing functions in between your cell phone and your PC or laptop via USB port.