OMCreate 9-Cell Laptop Battery for HP 620 / HP Probook 4525S 4420s 4320 4320s 4320t 4321 4321s, fits PH06 PH09 593572-001 593573-001 - 12 Months Warranty Battery type: Li-ion; Voltage: 11.1V; Cells: 9-cell; Operation time: 3 - 4 hours. Actual operation time varies depending on types of the device and the way it is used. Grade A cells ensure fast charges and low power consumption; Built-in circuit protection ensures both safety and stability. Compatible part number: 587706-751 / 593572-001 / 587706-761 / 593573-0011 / 587706-121 / ?HSTNN-IB1A / HSTNN-CB1A / HSTNN-DB1A / HSTNN-LB1A / HSTNN-Q78C / HSTNN-Q78C-3 / HSTNN-Q78C-4 / HSTNN-Q81C / HSTNN-W79C-5 / HSTNN-W79C-7 / ?BQ350AA / HSTNN-CB1A / HSTNN-CB1W Compatible Models: HP Compaq 320 321 325 326 420 421 620 621; HP 420 425 4320t 620 625; HP ProBook 4320s 4321s 4325s 4326s 4420s 4421s 4425s 4525s 12-months hassle-free warranty service. Please check if this battery is compatible with your computer before purchasing. Part numbers of compatible batteries and Computers are listed as following.