Metric Inverted External Ring System of Measurement Metric Location Style External Thickness 1.2 mm Fits Shaft Diameter 18 mm For Bore Diameter Not Applicable Fits Groove Diameter 17 mm Fits Groove Width 1.3 mm Fits Groove Depth 0.5 mm Free Inside Diameter 16.5 mm Free Outside Diameter Not Applicable Clearance Diameter Not Applicable Material Spring Steel Material Grade/Class 1060-1090 Tensile Strength Not Applicable Ring Type Inverted External Ring