This is a conic diffuser to be used as a light painting tool.
The cone is designed to have a homogen glow along the whole length if used with a normal flashlight, or if you have a focus-able flashlight you can focus the glow on the top or bottom (like you can see in the example photo)
The cap is designed to fit into my flashlight adapter or self made RGB flashlight (blade tool).
Designs can be found here:
http://www.thingiverse.com/thing:1444585 (blade tool)
http://www.thingiverse.com/thing:1316926 (flashlight adapter)
All parts are designed to be printable without any supports.