The Fein 92604341020 ProCORE AS 4.0 18V 4.0Ah Li-Ion Battery is ideal for trade professionals and DIY enthusiasts that use Fein cordless power tools. That being said, because this is part of Fein's AMPShare series, not only is it compatible with all other Fein AMPShare cordless tools but also Bosch Professional 18V cordless systems as well. This makes it a truly versatile battery pack, but it is also highly efficient. Fein's Electronic Cell Protection prevents overload, overheating and total charge so that this battery performs at its best and for longer. This product is sold as a single unit. Features Provides extreme performance and longevity for long lasting use Electronic Cell Protection prevents overload, overheating and total discharge Offers impressive flexibility. It .