The Hikoki BSL1840M 4.0Ah 18V Battery is a compact battery that delivers impressive power levels despite its size. The battery includes 3 way protection including deep discharge and overload protection. Fast re-charge plus energy saving extends the life of the battery and ensures that you can keep working with less downtime. Up to 1,500 cycles rechargeable through multiplex protection circuit that prevents overload, overcharge and over discharge