DEWALT 20V MAX Battery Adapter Kit, 18V to 20V, 2 Batteries and Charger Included (DCA2203C) - - Amazon.com
Amazon.com: EID for Dewalt 20V to 18V Battery Adapter, 2-Pack DM18D Upgraded Version DCA1820 Converter for Dewalt 18V/20V & for Milwaukee M18 18V Battery to Work for Dewalt 18V Nicad & NiMh
Amazon.com: 2Pack 18V 3600mAh DC9096 DC9098 Replacement Battery Compatible with Dewalt 18 Volt Battery DC9099 DW9098 DW9099 DW9095 DW9096 DE9039 DE9098 DE9503 and DC9310 Charger for 7.2-18V Ni-Cad Ni-Mh Battery : Tools