This replaced the rear sight carry handle on my Bushmaster AR-15 flat-top. It put my red-dot right above the fixed front sights. You need a riser like this to not obstruct or co-witness w/front sights. It is solid and matches the same build type of the gun, the retaining screws are exact replicas of the ones on the carry handle that I removed. 
Pros: Perfect compliment to the AR-15 build type
Cons: none
                    
This review was written in the old system and had content requirements that are different than reviews written today.