I purchased this hoping it would work on my CenterPoint 4-16x 40mm scope which I have mounted to my Ruger 10/22. It screwed directly into scope with no problem. You do have to unscrew the CenterPoint front ring prior to installing.
Pros: Works on the CenterPoint 4-16 40mm Scope.
Cons: Non
This review was written in the old system and had content requirements that are different than reviews written today.