CellularFactory: Dell Latitude D400 312-0078 Replacement Li-Ion Laptop Battery (3800 mAh) High quality replacement Lithium-Ion laptop battery rated at 3800 mAh Laptop battery is made using the highest quality cells available and utilize all of the proper logic boards thermal protectors thermistors and circuit breakers to ensure the highest levels of battery safety reliability and efficiency. Replacement rechargeable battery for you to keep as an extra power source handy. This Replacement Battery is 100% compatible with the original laptop battery.