Your new favorite mod uses a 20700/21700 but you still have a bunch of good 18650's? 3D printed 18650 to 20700/21700 adapter! : r/electronic_cigarette
Amazon.com: 18650 to 21700 and 20700 Adaptor : Electronics
Aces Of Vape - New!! The iJoy Captain PD270 *234 max wattage *Dual 20700 batteries included *18650 battery adapter sleeve included *Pass through charging *0.05-3.0ohm resistance range If you want power and
EASTERN(イースタン) RAMP PEG V2 - BMX通販|BMXパーツ|初心者おすすめBMXフレームパーツ専門店 Vancho bike
Vapesoon 18650 to 20700-21700 Battery Adaptor - Bitandpieces Vape