Go to Amazon Sites : br br TechOrbits replacement battery for Dell Latitude E Series E6400 E6400 ATG E6500 E8400 E6410 br br Battery type Li-ion Capacity 4400mAh Cells 6-cell Voltage 111V br 100 New from Manufacturer Up to 500 recharge cycles over the life of the battery TechOrbits is the only laptop battery brand to offer a 3 year warranty br CE-FCC-RoHS-Certified for safety 2 hour email response time 247 the friendliest support on the planet br Texas Instruments main board inside for fast chargingdouble overcircuit protection for extra safety br Operation time standard 4400mAh batteries provide about 2 hours of operation time the actual operation time will depend on hardwaresoftware being run as well as power management settings and the laptops energy efficiency