Threaded Flashlight Tube Extension To Fit A 18650 Battery (25mm tube)

This is a simple tube extension for an inexpensive type of LED flashlight. The flashlight normally takes three AAA batteries that are held in a caddy, These AAA caddies are often used to replace an 18650 battery, so it seemed like a good idea to do the reverse. Of course the big gain in battery capacity is a side bonus. :-)

Ideally this extension would be printed in one of the new conductive plastics since the metal tube of the flashlight is the ground return. I don't have any of that plastic