This is a diffuser created for the LED Lenser P7.2, but will fit any flashlight with a 37mm diameter head. I created this to test transparent PETG filament from extrudr and the results are great. The normal version has a wall thickness of 1mm, which works great for transparent materials. I also created a 0.5mm version if you want to use non transparent materials.

The design of the diffuser differs from usual designs, because the flashlight i used has a focus functionality. With the little bulging of this diffuser you can change the light intensity along the diffuser using the focus settings. This way you can either get a full illuminated diffuser or a sweep from very bright tip down to dim bottom (or anything in between).