TechOrbits battery for Dell Latitude E6400 E6400 ATG E6500 E8400 E6410 E6510 Presicion M2400 M4400 M6400,fits 312-0748 312-0749 PT434 NM633 KY265 KY266 KY268 KY477 PT437 PT436 9 cell 3 years warranty Battery type: Li-ion; Capacity: 6600mAh; Cells: 9-cell; Voltage: 11.1V 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 CE-/FCC-/RoHS-Certified for safety; 2 hour email response time 24/7; the friendliest support on the planet Texas Instruments main board inside for fast charging;double overcircuit protection for extra safety Operation time: standard 4400mAh batteries provide about 2 hours of operation time; the actual operation time will depend on hardware/software being run as well as power management settings and the laptops energy efficiency