Metal M48 to M48 Male to Male 48mm to 48mm M48-M48 Step Coupling Ring Adapter for Lens Filter Telescope

This is a pretty simple review since this is a M48 M-M coupling device. Sometimes these don't thread smoothly since the pitch is not very good but these are correctly matched to 0.75mm as expected. No issues or any concerns. They are decently machined and finish looks clean. Would buy more of these if needed.

Threads are extremely coarse and immediately locked together with my filter drawer. I had to completely destroy the ring to remove. Luckily that was not hard to do and done with minimal damage to my filter drawer. It was in my possession for all of 1 hour. Use with extreme caution to avoid locking.

Metal coupling ring. Threading is well done. Allows me to connect needed adapters for my telescope,