Use a 20V Battery on Your 18V DeWalt Tools With This Handy Adapter — Construction Junkie
DEWALT 18V to 20V MAX Lithium-Ion Battery Adapter Kit (2 Pack) DCA2203C - The Home Depot
DEWALT Charger for 7.2V-18V Battery, 1-Hour Fast Charging (DC9310) , Yellow - Cordless Tool Battery Chargers - Amazon.com
Custom Production Modified Soldering Iron Station Cordless Battery Powered For Dewalt 18v 20v Max Battery (without Battery) - Power Tool Accessories - AliExpress
DEWALT 18V-20V Adapter/Battery Combo Kit by DEWALT at Fleet Farm