EAGTAC 18650 To 21700 Converter Adapter For 21700 Flashlight, 18650 Battery Protective Sleeve, 18650 Battery Spacer, 18650 Battery Holder For TX3V T25V G3V S25V 21700 Battery Torch - - Amazon.com
3x C-Size to 18650 Battery Adapter – Divecenter
2 Pieces 18650 battery to 26650 Adaptor Converter adapter 18650 tube for 26650 led flashlight torch|battery led tube|battery tubetube house - AliExpress
18650 Battery Adapter For 20700 / 21700 Mods - iVapour
3D Printable 18650 Cell to 2x C-Cell Battery Adapter by Derek Tombrello