0.5 to 0.025″ Expansion Diam, 1,900 Lb Holding Force, 1/4-20 Mounting Screw, Stainless Steel ID Expansion Clamp 1/2″ Flange Diam, 1/2″ Flange Thickness, 1/2″ Mount Hole Diam, 1 Mount Hole, 3/4″ Overall Height