Part of the ONE+ system this Ryobi 18V 4.0 Ah battery is compatible with the full range of ONE+ tools for the home & garden, but is ideally suited to heavy-duty applications such as grinding, sanding & cutting. Ryobi Lithium+ technology provides more power, longer runtimes, & better durability than previous battery technologies, & unlike Ni Cad, does not suffer from 'memory effect'. Featuring a tough pack design with built-in impact protection for long-term durability & a rubberised base. The 4-stage fuel gauge displays remaining power (100%, 75%, 50%, 25%) so you always know how much power you have left. Lithium+ cells hold their charge over a prolonged period without losing power, ensuring batteries are always charged & ready to go. Battery sold separately. We've been perfecting the ONE+ system for over 20 years. Our ONE+ batteries are compatible with all ONE+ tools. Our tools are built to last & so is our warranty; 3-year warranty is included on all Ryobi ONE+ batteries.