18 Volt, One 2Point 0Ah, Compact Lithium-Ion Battery, Ryobi P161 (P190 2 Pack).

This 2-Pack Lithium-Ion 18-Volt ONE+ 2.0Ah Battery provides users with up to 2X more runtime than a typical Ni-Cd battery. The extreme weather performance battery is designed to withstand frigid weather conditions while providing fade-free power for maximum performance.