Amazon.com: AMICROSS Battery Adapter Replacement for Dewalt 18V to 20V Converter DCA1820, Convert Your Old 18V XRP Tools to Run on The Latest Dewalt 20 Volt and Milwauki 18V Lithium Batteries 2-Pack :
DEWALT 20V MAX Battery Adapter Kit, 18V to 20V, 2 Batteries and Charger Included (DCA2203C) - Amazon.com