ARyee 4400mAh 6535B Battery Compatible with HP EliteBook 6930p 8440p 8440w, HP ProBook 6440b 6445b 6450b 6540b 6545b 6550b 6555b

hi this is Sarah - voice with laptop battery express this 9 sell HP battery is rated at 7800 milliamp hours or 87 watt hours and will give you about 3 to 5 hours of runtime depending on your energy use the mah or milliamp hour and the W HR or watt hour indicates how long a battery will run on a charge the higher the milliamp hour and watt hour number the longer the battery will run all of our batteries are brand new with Samsung Power Cells a Texas Instruments computer chip and are never used or refurbished if you're finding less expensive batteries on line please be aware that it's because they use cheap quality power cells inside the cartridge that can easily wear out in six months our batteries typically have a service life of three to five years all batteries from laptop battery Express come with a 30 day money back gaurantee and a full 12 month warranty all of our batteries shipped