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 , which can charge virtually all smartphone li-on batteries in the market. * 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. * You only need 2 pins to charge a battery. Here is the instruction: * To Charge the battery for Samsung Behold SGH-T919 , 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. * The LED Light will turn Red when charging the battery, turn blue to indicate the battery is fully charged. * Input: AC 100-240V 50/60Hz 150mAh. * Output: DC 4.35V 600mAh ¡À 50mA. * USB Port Output: 5.2V 1000mAh. 2)New 1380mAh Rechargeable Li_ion Battery: * Brand:Sporting Persistence . * High quality Li-Ion battery. * Battery Type: Lithium Ion. * Battery Capacity: 1380mAh . * Voltage: 3.7V. * Best Replacement for the original battery with comparable standby and talk time . * Our battery is sent out with little or no power, so please charge it for about 6 - 12 hours before using. Fish Bone Winder Rubber: * Unique cable winder for organizing your earphone cord * Compatible with Headphone Cable,Telephone.Cable, Mouse Cable,etc * Size: 6.4 cm x 2.8 cm Material: Silicone