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 ZTE Avid 4 , allow the 2 metal pins on the charger to touch the 2nd and the 4th contacts of battery. * For other batteries, it's not necessarily to be the 2nd and 4th 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 2600mAh Rechargeable Li_ion Battery: * Brand: Unbranded/Generic . * High quality Li-Ion battery. * Battery Type: Lithium Ion. * Battery Capacity: 2600mAh . * Voltage: 3.8V. * 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. 3)Screen Touch Pen: * Soft touch tip material prevents scratching to.the screen very smooth tip * suitable for drawing,jotting notes,playing games and navigating on your device. * Lightweight copper body 1.Smooth Movement. 2.Lightweight body (5g) 3.Finger Pressure