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. ============================================= 1)Universal USB/AC Charger: * This is an universal charger, the top panel could be slided and the metal contact pins are also moveable. * You can slide it back and forth to fit virtually any size of Li-On batteries in the market. * Please see our Title pictures for detail * Here is the instruction * To Charge the battery for ZTE Warp Sequent N861 (Boost Mobile) , allow the 2 metal pins on the charger to touch the 1st and the 3rd contacts of battery. * For other batteries, it's not necessarily to be the 1st and 3rd though, please refer to the user manual. * 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. 2)New 2100mAh Rechargeable Li_ion Battery: * Brand: Sporting Persistence . * High quality Li-Ion battery. * Battery Type: Lithium Ion. * Battery Capacity: 2100mAh . * Voltage: 3.7V. * Best Replacement for the original battery with comparable standby and talk time . 3)Micro USB 2in1 Cable (3 Feet/1M): * 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.