Impact-resistant outer case and shock-absorbing inner-liner are engineered to protect the battery. Sixteen contact terminals maintain a constant connection with the tool to help prevent power loss or fluctuation， even during high-vibration applications. Battery resists self-discharge and remains ready for use even after long periods of storage. Delivers consistent power and run time in extreme temperatures (-4 F/-20 C). Integrated LED (light emitting diode) battery charge level indicator allows user to monitor battery charge. Equipped with Star Protection Computer Controls to protect against overload， over-discharging and over-heating. For use with all Makita 18V lithium-ion power tools.