GFI 10.8V 5200mAh Laptop Battery 76+ for Lenovo ThinkPad E550 E550c E555 Series 100% brand new from manufacturer. Under 100% Aging Test. Up to 502 cycles life, low self-discharge, no memory effect; Dual IC chips provide protection against short circuit, over-discharge, overcurrent. CE/FCC/RoHS certified for product safety. 24/7 email support, 14-month hassle-free warranty. Grade A Cell ensures fast charging and low power consumption; Built-in circuit protection ensures both safety and stability. Operation time for standard batteries(6-Cell, 4400mAh): Around 4 hours, the actual operation time will depend on how much electricity is required by the device and how you use it.