This is a simple cap for the H2R Flashlight from Olight.
It is used to attach colored diffuser to the flashlight to write or draw something in the air in a long exposure to create lightpainting art.
Print the part that goes on the flashlight in black and the color cone in any color you desire. The cone should be thin enough that even opaque materials will create an effect. For brighter results use translucent materials. But keep in mind even on lowest brightness highly transparent materials might be too bright.