Changing Mirror
diameter 20mm, thickness 3mm or less with adapter.
when I unscrew my mirror and look through I find out why it crack.
the coating was gone, poor product surely, but maybe also due to cleanning friction. make your own conclusion.
I’ve been wondering if not cleaning and having excess soot or debre on it could cause excessive heat to build up and damage? I did see a video where a guy had a low cost beam combiner/reflector and installed it backwards (so the um-coated side was facing the laser) which caused immediate burn/break when the laser was fired.