This Ryobi OP4026 40-volt lithium-ion battery and OP400 40-volt lithium-ion charger is a must-have for any power tool enthusiast. With its advanced technology and high-quality construction, this battery and charger combo is designed to provide reliable and long-lasting power for all your power tools.Whether you're a professional contractor or a DIY enthusiast, this battery and charger combo is perfect for keeping your power tools running smoothly and efficiently. With its 40-volt lithium-ion technology, this battery and charger combo offers a powerful and long-lasting charge, making it an ideal choice for all your power tool needs. They were with a lawnmower that failed. Too expensive to repair, Also comes with a replacement battery (aftermarket)