Coolgo New Laptop Battery for HP Elitebook 2530P 2540P; Hp Compaq 2400 2510P; Hp 2533T Mobile - 18 Months Warranty [li-ion 6-cell 5200mAh 10.8V] HP 10.8V 5200mAh Black 6 Cells laptop battery For Hp Business Notebook 2400 2510p nc2400 P/N's: 412779-001 HSTNN-FB21. Quality Certication: All the products pass the ISO9001, CE and ROHS, FCC multiple international authentication and completely accord with environmental protection requirement. Consummate Design: Excellent design makes the product not only has the overcharge, discharge and short circuit multiple protection, but also to balance charge-discharge of all the internal cells. Environmental Test: Standard modern assembly line. All products have passed a variety of charge-discharge and aging test before they leave the factory. 100% quality test for all items. Operation time: For standard battery(6-cell, 4400mah): 2-3 hours; for extended battery(12-cell, 8800mah): over 4 hours (Note: The actual operation time depends on how much electricity is required by the device and how you use the battery.)