I bought a bunch of these Kootek flashlights because they're small and cheap, so it's easy to throw them in whatever vehicle/bags I want without worrying about it. I wanted to make a light diffuser that would function as both a "lantern" to help light up a room, but also as a decent "safety light" when used with flashing mode while walking or biking. Huge thanks to iggyggi for the SCAD file, it made this much easier to mess around with.

Due to the way these lights are shaped, I was actually able to make a large diffuser that will "clip" onto the front of the light for high visibility (2.5 inches of illuminated material), but will also store on the back of light to keep it small for storage (it adds less than 1/4 inch to the length of the flashlight when stored).

The head of the Kootek lights (at least the versions I have) are right around 22.5mm, I found that printing the diffuser with a 22.6mm ring made it the right size to fit over the head without being too tight or too loose, obviously printer tolerances may make this different for different printers.

In case anyone else wants to recreate this with iggyggi's original SCAD file, here are the values I used for this model:

//Bottom Diameter / Outer Diameter of the head of the lamp
d1=22.6; //[10:0.1:80]

//Top Diameter
d2=22.6; //[5:0.1:50]

//Height of the cone
h=53; //[10:1:100]

//Height of the ring
h_u=5; //[0:1:20]

//Thickness of the wall
wall=1; //[0.1:0.1:3]