Hex nut model Double torx screws to hold your scope firmly in place Designed for Weaver/Picatinny rail fitting Solid steel construction for superior strength Weaver Low : Configuration: 2 Piece Ring Size (Diameter): 1 / 25.4mm Height: Low Rail: Weaver Fixings (Top Cap): Double Torx Screw Fixings (Rail): Hex Nut Internal Cushion: NO Retractable 'Recoil Stop' Pin: NO Height: 37mm / 1.5 Weight: 129g / 4.6oz Weaver Medium : Configuration: 2 Piece Ring Size (Diameter): 1 / 25.4mm Height: Medium Rail: Weaver Fixings (Top Cap): Double Torx Screw Fixings (Rail): Hex Nut Internal Cushion: NO Retractable 'Recoil Stop' Pin: NO Height: 41mm / 1.6 Weight: 149g / 5.3oz Weaver Large : Configuration: 2 Piece Ring Size (Diameter): 1 / 25.4mm Height: High Rail: Weaver Fixings (Top Cap): Double Torx Screw Fixings (Rail): Hex Nut Internal Cushion: NO Retractable 'Recoil Stop' Pin: NO Height: 47mm / 1.9 Weight: 174g / 6.1oz