For use with the Stihl Compact Cordless System, the AK 20 is a 36v rechargeable lithium battery with a capacity of 118 Wh. It features an LED charge level indicator. The run time you can expect from this battery depends on the tool & operation it is used with. Charged to 100% with AL 101 charger: 150 mins Charged to 100% with AL 300 charger: 45 mins Charged to 100% with AL 500 charger: 45 mins Specification: Battery Type: Lithium-ion Battery Battery Voltage: 36 V Battery Capacity: 3.3 Ah / 118 Ah Weight: 1.2kg Warranty: 2 Year