Two-pack combo of the popular RYOBI 40V 4.0 AH battery. Compatible with all RYOBI 40V Lithium tools and chargers, the 40V 4.0 AH Lithium-ion Battery is the perfect addition to your RYOBI 40V tool collection. It's lithium-ion cells deliver fade-free performance from start to finish. The convenient on-board battery life indicator keeps you informed while you're out in the yard tackling your landscaping jobs. The 40V 4.0 AH OP40404 Lithium-ion Battery's extra cell capacity is perfect for higher output tools like 40V mowers, blowers and chain saws. Ryobi 40V Lithium surrenders nothing but gas.