A custom cut and bored out M*g 4C to size of 3-1/5 "C" (10mm longer than 3C) which will work as: 1- 2x26650 (7.4V, 5200mAh)
2- 2x21700 (7.4V, 5000mAh)
3- 3x26500 (11.1V, 3000mAh)
4- 3x25530 (11.1V, 3300mAh)
Outside barrel is fine grooved for better grip and black hard anodized.
These are available as just battery barrel, with or without switch, with or without switch with or without head, Boro lens and aluminum reflector.
I have few of these if anybody else interested.
Please PM for your prefered host. Some bulbs are also available.