6.0 Ah battery offers ultimate run time for prolonged, heavy-duty applicationsLED charge level indicator displays approximate remaining battery powerBattery Protection System provides Over-Discharge, Temperature and Current Protection for enhanced performance, battery cycle life and overall battery life (when used with STAR marked tool)Li-Ion Batteries offer extended run time versus Ni-Cad and Ni-MH batteriesLi-Ion Batteries offer more cycles over the life of the battery versus Ni-Cad and Ni-MH batteriesOptimum Charging System utilizes 3 Active Controls (Current, Voltage & Temperature) to maximize battery lifeBuilt-In Memory Chip communicates with Charger CPU to optimize the charging process based on the unique conditions of each battery