Effective on hard and soft shaftsDesign fully engages the shaft without marring360 degree clamping forceEasily installed where major disassembly would otherwise be requiredZinc plating provides moderate corrosion resistanceSpecification: locking device: Clampscrew / locking style: Hex Socket Cap Screwconstruction: One Piece - Splitfinish: Zinc Platebore type: Plainscrew material: Stainless Steel - ASTM F837inside diameter: 2.9375 inscrew size: 3/8-24 x 1 inoutside diameter: 4.2500 inpart weight (oz.): 28 ozwidth: .8750 inharmonization code: 8487.90.0080material: Steel - ASTM A108type series: 1Cadditional details: Effective on hard and soft shafts - Design fully engages the shaft without marring - 360 degree clamping force - Easily installed where major disassembly would otherwise be required - Zinc plating provides moderate corrosion resistance.