I just got my shipment of two of these. Quality and finish is very good. There's a barrel nut tensioning latch on the top and bottom. So the rail fits and locks up very tightly. Rail height dimensons match the M4 RAS which a good thing. This rail doesn't have the cuts for the RAS Panel clips so I used alternative rail covers for the unused pic slots. Overall an outstanding quad rail.

This is an excellent rail interface for the money. It locks up solid, is lightweight, and has a built in heatshield. My only gripe is that it does not have the correct dimensions to accept Knights Armament Rail Panels like a lot of US domestic rail systems do, but it obviously wasn't designed for them. This rail looks great on my C8 SFW.