Amstron's 6 cell Lenovo FRU 42T4504 Laptop replacement Battery is rated at 10.8V, 5200mAh, 56Whr. This replacement Battery for Lenovo FRU 42T4504 is 100% compatible and will meet or exceeds original specification. This FRU 42T4504 replacement battery made by Amstron has been tested for safety and designed for high performance.