Optical shutter / beam block for Thorlabs-style cage mounting

thingiverse

Inspired by Tjsangster's peep hole cover, I added a Thorlabs-style 30 mm cage mounting so I could use it in an optics lab. It's a nice quick 30 minute print :) **Don't use it to block laser beams without testing it first** (with a *significant* safety margin!), it will absorb the light and get warm and melt. It will work great for protecting sensitive spectrometers and detectors, a simple slit for a microscope lamp, etc...