1 x Milwaukee Battery at 18 V, 5.0 Ah Milwaukee Battery delivers up to 2.5x more run time, up to 20% more power and up to 2x more battery life compared with other Lithium-Ion technologies and / or with previous MILWAUKEE® battery technology. (Results depend on tool and application) REDLITHIUM™ protection with REDLINK™ digital overload protection to prevent users from damaging their cordless power tool investment in abusive situations Battery has individual cell monitoring that ensures optimal charge and discharge for maximum life Durable metal frame battery construction with shock responsive separators preventing pack failure from excessive vibrations or drops Battery has water protection that routes water away from the electronics & out of the battery pack Battery can be used in extreme temperatures down to -20 °C without compromising on runtime and battery life On-board battery fuel gauge helps the user to maximize his battery run-time efficiency