Makita 18V Li-ion 4.0 Ah 2-Pack features the Makita 18V LXT Lithium-Ion battery, designed to charge faster and deliver longer run time than standard Lithium-Ion batteries. This battery pack performance and productivity, for tackling the most demanding applications. With 35% more run time per charge d to the Makita BL1830 battery and a rapid charge time of just 40 minutes, it maximizes your work efficiency by spending less time on the charger. The 18V LXT 4.0 Ah battery (BL1840) is compatible exclusively with STAR Protection tools, which are identified by a star symbol or yellow battery receiver on the tool. These batteries resist self-discharge, ensuring they are ready for use even after extended storage. For optimal charging, the Makita Rapid Optimum Charger (sold separately) uses smart technology to monitor current, voltage, and temperature, helping to extend battery life while delivering a faster charge. Its built-in fan cools the battery during charging, maintaining efficiency even in hot conditions. Additionally, Makita’s Star Protection Computer Controls enable -time communication between the tool and battery to protect against overloading, over-discharging, and overheating. As an innovation leader in cordless tool technology, Makita a comprehensive lineup powered by 18V Lithium-Ion slide-style batteries. Model Number: BL1840