This 3.0 Ah 18V lithium ion battery 2 pack from Makita offers maximum run time for prolonged, heavy-duty applications. Features include a battery fuel gauge that indicates approximate remaining battery power, a battery protection system providing over-discharge, temperature and current protection for enhanced performance, battery cycle life and overall battery life (when used with STAR marked tool; sold separately). The optimum charging system utilizes 3 active controls (current, voltage and temperature) to maximize battery life and a built-in memory chip communicates with the charger CPU to optimize the charging process based on the conditions of each battery.