It's a ring of metal with threads. Not much to go wrong.

OPT does s good job. The only issue these days is having things in stock. These adapters were in Stock. Timely delivery.

Fast shipping -- thin, but well made and doesn't add to length of imaging train for back focus.

I use this to step down my wide T-Adapter for my Canon EOS Ra from 48mm to the "standard" 42mm to fit my Astro-Tech 0.8 Reducer (really need to find a reducer for my 80mm / 480mm triplet that has 48mm threads!) It works well and have not had any issues.

Purchased this to replace adapter on my ZWO EFW. Worked perfectly.

I like this adapter, it's good quality. I use it to connect 2" Twist lock adapter to Baader T2 Prism. Works like a charm!