Everything looks right to me. 1.25" eyepiece adapter. The listing confuses things by saying it is an M42 adapter (they mean male 42mm). The thread pitch is listed as 0.75 which is correct for T-threads so you should be good there.
Personally I would spend a few more dollars and get a good quality T-adapter. The "Top Rated" product you listed has one review of 3 out of 5 stars.
I have a couple of the below brands in different mounts. The quality is very good to excellent. I bought Vivitar branded adapter that was made in India. Everything was terrible about it - rough finish and it wouldn't even thread into any of my telescope adapters.
Qualide T-Mount Lens Adapter for Pentax K 35mm SLR Film Camera 25-166-2227 | eBay