External Grip Ring System of Measurement Inch Location Style External Thickness 0.042 in Fits Shaft Diameter 5/16 in For Bore Diameter Not Applicable Fits Groove Diameter 0.303 in Fits Groove Width 0.048 in Fits Groove Depth 0.005 in Free Inside Diameter 0.298 in Free Outside Diameter Not Applicable Clearance Diameter Not Applicable Material Steel Finish Black Phosphate Material Grade/Class Not Graded Tensile Strength Not Applicable Ring Type External Grip Ring