The Knights Armament Rail Mounted Anti-Cant Device is a simple, low profile tool that helps precision shooters ensure that their rifle is level before breaking a shot. It incorporates a small bubble level into an aluminum base that sits low enough to permit its use under most optics. Attaches to any M1913 Picatinny rail surface via a screw and clamp arrangement.
This is a new old stock Knights authentic factory manufactured product. MPN: KM-30855
For a review of the Knights product, see: Soldier Systems review of KAC anti-cant device