SpecificationsModel: 01AV423 (61), Type: Li-ion. Voltage: 11.4V. Capacity: 24Wh 2100mAh. Up to 1000 recharge cycles over the life of the battery Compatible Laptop ModelsFit for Lenovo ThinkPadT470, T570, A475, A485, T480, T580, P51S, P52S,TP25 (Anniversary Edition 25) Series. (NOTE: this battery will NOT fit for the T460S T470S T480S laptop) Replace Part NumberFor Lenovo ThinkPad 61, 61+, 61++ battery. For Lenovo ThinkPad 61 01AV423, 4X50M08810, 01AV422, SB10K97579, SB10K97580, 01AV424, SB10K97581.For Lenovo ThinkPad 61+ 01AV425, 4X50M0881, 01AV491, SB10K97582, SB10K97583, 01AV426, L18M6P71. For Lenovo ThinkPad 61++ 01AV427, 4X50M08812, 01AV428, SB10K97584, SB10K97585 Advantage for batteryBrand New Grade A cell battery, all Vanpir batteries are certified by UL / CE / FCC / RoHS for safety and Strict guidelines for compatibility. Now, this battery is powered by Lithium-Ion technology and has a safeguard chip that authenticates. System Battery Extended Life System Bat