The Stihl AP200 4.8Ah 36V Battery is compatible with the tools in the STIHL PRO Cordless AP Power System. It features a charge level indicator on the top with four LEDs so you can see how much charge you have left quickly and easily, at the touch of a button. Stihlbatteries feature an intelligent battery management system - this clever technology gives a constant level of power whether the battery is 100 charged or 1 charged.