DEWALT 20-Volt 4 Amp-Hour; Lithium Power Tool Battery Kit (Charger Included) in the Power Tool Batteries & Chargers department at Lowes.com
20V MaxLithium 4.0 Ah Battery - Rockwell Tools
Amazon.com: Avid Power 20V MAX Lithium Ion Rechargeable Battery with Real-time Capacity Indicator and USB Output, Only Compatible 20V Cordless Tools : Tools & Home Improvement