It wouldn't fit on my rail out of the box. I had to do some filing on the inside tracks to make it fit. Anyone w/a file and a few minutes can do it. Once in place they fit securely. I have mounted a couple of different optice to them without issue.
Pros: Solid, stays secure
Cons: Needed some filing to fit my picatinny rail
This review was written in the old system and had content requirements that are different than reviews written today.