Most of our battery packs are made up of authentic Grade A 18650 battery cells from Korea or Japan. We use Samsung,Panasonic or LG brand cells and and some use our brand cells. Battery management system (BMS) is the the circuit board that protect your battery pack and make sure it is safely. 100% test every battery, Cycle life:800-1000 Times. Warranty:1 years, Certificate:CE/ROSH/MSDS/UN38.3 Package Type:include battery, charger, keys etc, 1 battery pack for 1 carton, be shipped from USA warehouse Application: universal mountain ebike, Fit Motor:1000W 1500W.syi