The Ryobi 18-Volt ONE+ system introduces lithium-ion performance at Ni-Cad prices. The 18-Volt ONE+ Compact Lithium-Ion Battery provides up to 20% more run time, holds a charge 4x longer and is 45% lighter weight than 18-Volt ONE+ Ni-Cad batteries. Best of all, like all 18-Volt ONE+ batteries, it works with over 50 great ONE+ tools. This 2 pack of lithium-ion ONE+ batteries is a perfect addition to any ONE+ collection. Compatible with over 50 great Ryobi 18-Volt ONE+ tools Compact lithium-ion battery compared to 18-Volt Ni-Cad (P100) 45% lighter weight reduces user fatigue Compact size allows use in tight areas