BlackBerry Curve 8520 Battery with Cover - Extended, Li-ION, 1800mAh. High Capacity rechargeable battery rated at 1800 mAh for your cell phone Expect to Approx. Double Your Talk and Standby Times Extended battery for you to keep as a reliable extra power source handy Advanced technology keeps phone working at optimum performance. Includes a battery cover that is specifically designed for the battery and your phone