Amazon.com: uxcell AAA Battery 3x1.5V Storage Adapter Case,18650 Battery Holder Converter for AAA LED Flashlight 1 Set : Electronics
18650 Battery Protective Sleeve Tube Battery Spacer Holder Converter for 18650 LED Flashlight - - Amazon.com
Fenix Alf-18 18650 to 21700 Battery Converter Adapter Tube Holder for sale online | eBay
Amazon.com: 18650 to 21700 and 20700 Adaptor Battery Storage Container(18650 to 21-700 and 20-700 Adaptor) : Musical Instruments
2 Pieces 18650 battery to 26650 Adaptor Converter adapter 18650 tube for 26650 led flashlight torch|battery led tube|battery tubetube house - AliExpress
18650 to 21700 battery adapter
3pcs Standard 3 AAA Battery Holder Box Case To 18650 Converter Adapter | eBay
EagTac 18650 to 21700 Spacer / Adapter
Amazon.com: LampVPath 6PCS 18650 Battery Protective Sleeve, 18650 Battery Spacer, 18650 Battery Holder Converter for 18650 Battery (Batteries are not included) - 6 Pack : Electronics