Good solid mount. Attached mine to a 20 ga shotgun mag tube but can attach to virtually any size barrel/tube. I didn't put any lock-tight on the screws so after a box or 3 of shells it started to come loose, but was easily remedied.
Pros: easy, simple to install,
Cons: remember to use some loctite if you want it secure
This review was written in the old system and had content requirements that are different than reviews written today.