The Arisaka Optic Leveler is an inexpensive, easy-to-use tool for leveling scopes mounted in rings or one-piece mounts. The base plate sits on the Picatinny rail or one-piece mount just below the turret cluster of the scope, and then the matching wedge is inserted from the side. As the 11 degree ramped surfaces of the wedge and base engage, the top of the wedge rises upwards and contacts the turret cluster, automatically leveling it. This product includes the leveler base and both small and large wedges. The small wedge requires a space between the rail/mount and turret cluster from 0.190" to 0.730". The large wedge requires a space between the rail/mount and turret cluster from 0.680" to 1.200".Features : (3) Piece Set 11 Degree Ramped Surface Material: 6061-T651 Black Anodized Aluminum Made In The USA