DavidEF
(DavidEF)
5
The manufacturers can safely introduce 21700 flashlights to the market, and people will buy them. There are already a lot of cheap flashlights that have a tube made to support either a 3xAAA holder or a 18650 cell. Most of those tubes will already support a 21700 cell by default. No change needed. Others might just need slight modification. Or a 18650/21700 sized flashlight can be made and people could opt to use 18650 until they get 21700 cells.