Parametric CO2 laser mirror alignment cover

Useful tool to align CO2 laser mirrors by following burning spot method, but protecting the mirrors , inspired by https://www.thingiverse.com/thing:760795

I have uploaded two STLs for mi Chinese mirrors:
54 x 54 using 50x50 PCB board
45.4 x 43.5 using 45x50 PCB board

You can edit to fit your mirrors!