'Internal Retaining Ring, Carbon Steel, Black Phosphate, For Bore Dia 18mm, Free OD 19.50mm, Thickness 1.00mm, Thickness Tolerance -0.060mm, Fits Groove Dia 19.00mm, Groove Dia Tolerance +0.13mm, Fits Groove Width 1.10mm, Fits Groove Depth 0.50mm, Hole Dia 2.00mm, Meets DIN472, Rockwell Hardness RC47-54, Tensile Strength 150, 000 PSI, Package 50'