Product Review

You do not need a special back cover to use this battery
This package is specifically designed for Samsung Galaxy S2, Model SGH-S959G from Straight Talk/NET10 as we stated in our listing.
There are many Samsung Galaxy S II in the market, they all use different batteries. If you do not have Samsung Galaxy S2, Model SGH-S959G, this package is not for you.

100% Brand New.
2050mAh Rechargeable Li_ion Battery:
* High quality Li-Ion battery.
* Battery Type: Lithium Ion.
battery Capacity: 1800 mAh.
* Voltage: 3.7V.
* The best spare battery for your phone.
* 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.
* Keep an extra battery on hand for extend standby and talk times.
* Integrated microchip prevents overcharging and lengthens battery life.
Compatible models:
Samsung Galaxy S II , S959G (Straight Talk/TracFone/NET10)