The ONE+ 4.0 Ah High Energy Lithium-Ion Battery is a powerful and reliable energy storage solution designed for a variety of applications. With a battery voltage of 18 V and a capacity of 4 ampere-hours (Ah), this battery provides optimal performance for devices operating within the Ryobi ONE+ 18V battery system. The lithium-ion technology ensures a long lifespan and high energy density, meaning the battery operates efficiently and requires less frequent charging. The battery is available as a single unit and is ideal for use in various electric devices, from tools to garden equipment. It comes with a battery included, allowing for immediate use. This battery is an excellent choice for anyone who values performance and reliability and wants to operate their devices efficiently.