Beautiful mount. Precision engineered and a perfect co-witness. I own a gun shop in AZ so I see a bunch of products on a day-to-day basis, so I appreciate when I see products that stand out above the rest and this mount definitely does. It mounted up perfectly on my M4 without any hassle, the mount is rugged, there is no slop or wiggle in the design and the RMR fit perfectly in its place. Instructions were clear, concise, and easy to execute. If you are thinking about mounting an RMR to your shotgun this is the mount to get!!