Specifications: - Battery type: Li-ion - Voltage: 11.1 - Capacity: 4400 mAH - Brand: Unbranded /OEM Compatible Models: HSTNN-IB1A, HSTNN-CB1A, HSTNN-DB1A, HSTNN-CBOX, HSTNN-LB1A, HSTNN-Q78C, HSTNN-Q78C-3, 587706-761, HSTNN-Q78C-4, HSTNN-Q81C, HSTNN-Q81C-3, HSTNN-Q81C-4, HSTNN-W79C-5, HSTNN-W79C-7, HSTNN-W80C, HSTNN-I86C-3, HSTNN-I86C-4, HSTNN-I86C-5, HSTNN-I85C-3, HSTNN-I85C-4, HSTNN-I85C-5, HSTNN-LB1A, 587706-761, 587706-751, 593572-001, BQ350AA, HSTNN-CB1A Compatible part numbers: Compaq 320, HP 420, ProBook 4325s, Compaq 321, HP 425, ProBook 4326s, Compaq 325, HP 620, ProBook 4420s, Compaq 326, HP 625, ProBook 4421s, Compaq 420, ProBook 4320, ProBook 4425s, Compaq 421, ProBook 4320s, ProBook 4520, Compaq 425, ProBook 4321, ProBook 4520s, Compaq 620, ProBook 4321s, ProBook 4525s, Compaq 621, ProBook 4320t What's in the box 1 X HP Probook 4520S Compaq 620 Compatible Replacement Battery