The 18V Lithium Ion Battery (BSL1815X) is a powerful battery for a variety of Metabo HPT 18V slide-type power tools. It delivers 1.5 Amp Hour (Ah) of runtime and is compact and lightweight to reduce user fatigue. The Amp hour capacity refers to how long the battery can last before recharging. For protection from the elements, this battery features a resin coating. Its complex circuitry also prevents damage from overload, overcharge, and over-discharge of the battery.The BSL1815X battery charges the fastest on charger model UC18YSL3 (15 minutes). Other compatible charger models and charging times include: UC18YFSL (22 minutes) and UC18YKSL (40 minutes) (chargers sold separately). The Metabo HPT BSL1815X battery is warranted to the original purchaser to be free from defect in materials and workmanship for a period of 2-years from the original purchase date. Every Metabo HPT accessory is designed to the highest standards and is rigorously tested for both performance and durability.