18-Volt 5.0Ah LXT Lithium-Ion Battery (10-Pack)The 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 5.0Ah battery has a category-leading charge time of only 45 minutes, so it spends more time working and less time sitting on the charger. The 18-Volt LXT 5.0Ah battery is compatible only with Star Protection tools, indicated by the Star Symbol and/or Yellow Battery Receiver under the tool. 18-Volt Lithium-Ion batteries resist self-discharge so they're ready for use even after long periods of storage. The 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. For improved tool performance and extended battery life, created STAR Protection Computer Controls. STAR Protection is communication technology that allows the tool and battery to exchange data in real time and monitor conditions during use to protect against overloading, over-discharging and overheating.