Milwaukee M18NRG Starter Set includes 2 x M18B5 5.0 Ah batteries, M12-18 fast charger & FREE 1 x M12B2 2.0 Ah battery Starter Set 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  Individual cell monitoring of this Starter Set 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 Water protection of this Starter Set routes water away from the electronics & out of the battery pack Starter Set 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 REDLITHIUM™ protection with REDLINK™ digital overload protection to prevent users from damaging their cordless power tool investment in abusive situations