Amazon.com: aikeec Adapter for DeWalt to Milwaukee Battery, Battery Adapter for DeWalt 18 20V Lithium Battery Convert to for Milwaukee 18V M18 Battery Use for Milwaukee M18 Cordless Power Tool 2 Pack :
DEWALT 20V MAX Battery Adapter Kit, 18V to 20V, 2 Batteries and Charger Included (DCA2203C) - Amazon.com
Amazon.com: Bluetooth Speaker Fit for DeWALT 18v 20v Max Including 20-60v Flexvolt Battery for Worksite, Camping and Parties (Battery not Included) : Electronics