LS Accessories 1400 mAh Li-ion Battery for HTC Mytouch 4G (BD42100), HTC Thunderbolt (BTR6400B), and HTC Merge Battery (BD42100) is compatible with the HTC MyTouch 4G, HTC Thunderbolt, and HTC Merge 1400 mAh high quality Lithium Ion battery that charges to its full capacity for over 500 cycles Grade A batteries with Dual IC protection to ensure safety; Battery Voltage: 3.7 Volts Battery Energy Content: 5.18 Watt Hours This battery is not compatible with the HTC MyTouch 4G Slide