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 Microsoft Lumia 950( AT&T ) , allow the 2 metal pins on the charger to touch the 2nd and the 3rd contacts of battery. * For other batteries, it's not necessarily to be the 2nd 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. 2)New 3500mAh Rechargeable Li_ion Battery: * Brand: AceSoft . * Battery Type: Lithium Ion. * Battery Capacity: 3500mAh . * Voltage: 3.85V. * Best Replacement for the original battery with comparable standby and talk time . 3)Night Glowing Dual USB Car Charger: * LED Charging Indicator. * Input Voltage:12V or 24V DC * Output Voltage & Current * Port 1: 5V 2.1A * Port 2: 5V 1.0A 4)Micro USB 3.1 Data Sync Cable ( 3 Feet/1M ): * Type: USB 3.1. * Transmissinon Speed: 10Gbps. * Provides high-speed data transfer rates. Software is not included. * Charging your Cell phone by connecting this charging cable to our Wall charger or USB car charger. 5)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.