I put this on a 20 gauge 870 with the included spacers in less than 5 minutes I had a red dot mounted and ready to sight in. Comes complete with the screws spacers for 20 ga guns and an allen wrench.
Pros: Quick and sweet!
Cons: Can't really still use the bead sights
This review was written in the old system and had content requirements that are different than reviews written today.