The Makita 18-Volt LXT Lithium-Ion battery charges faster and works longer than standard Lithium-Ion batteries, giving you and your cordless tools unmatched performance and productivity to take on the most demanding applications. The Makita 4.0Ah battery, model BL1840B, combines more run time (35% more run time per charge than the Makita BL1830 battery) with a category-leading charge time of only 40 minutes so it spends more time working and less time sitting on the charger. For added convenience, it also features an on-board LED charge level indicator to monitor battery charge. The 18-Volt LXT 4.0Ah battery is compatible only with Star Protection tools, indicated by the Star Symbol and/or Yellow Battery Receiver under the tool. Makita 18-Volt Lithium-Ion batteries resist self-discharge so they're ready for use even after long periods of storage. The Makita Rapid Optimum Charger (sold separately) is a smart-charging system that communicates with the battery during the charging process to monitor current, voltage and temperature. This advanced charging technology helps optimize battery life and deliver a faster charge. In addition, the Charger has a built-in fan to cool the battery for faster and more efficient charging, even in hot weather conditions. This promotion also comes with a BL1840B-2 18V LXT Lithium-Ion 4.0Ah Battery, 2/pk and a bonus BL1840B-2 18V LXT Lithium-Ion 4.0Ah Battery, 2/pk.