RYOBI ONE+ 18V Lithium-Ion 4.0 Ah Battery (2-Pack) and Charger Kit PSK006 - The Home Depot
Ryobi P197 Battery ONE + (PLUS) Compatible Replaces P108 Rechargeable Lithium Ion 18 v Volt 4.0 Ah / 72 Wh UL Listed Faster Recharge Single Battery with Fuel Gage - Amazon.com