The Spuhr ISMS 1-Piece C series Gen 3 Scope Mount Picatinny-Style Matte has a slightly narrower ring closest to the shooter. It has a reinforced side plate and the ring closest to the shooter now has two screws instead of the old three screw design.The ideal scope mount system series of mounts feature seven set of interfaces to attach any of more than 40 different accessories and has a bubble level integrated in the rear plane of the mount body to prevent canting of the rifle. The rings are diagonally cut for increased visibility of the elevation and windage turrets (US Patent 8,733,011). The mounts are machined from billet 7000 series aluminum and all aluminum parts are hardcoat anodized. The Torx 20 ring and clamping screws are zinc-nickel coated for corrosion resistance and come pre-waxed from the factory to ensure proper torque values. The mount is shipped with a manual and a "wedge" leveling key. Note:The Spuhr ISMS 1-Piece C series Scope Mount C is designed for use with 56 mm ...