adapter sleeve specification:H23, H30,H31,H32series material:bearing steel,GCR15 hardness:59-63HRC class of precision:ABEC-1 product detail description: Model No. H seriesCategory Adapter SleeveSpecification 36*40*58mmMaterial TypeBearing steel, Carbon steelNumber of RowSingle Seal TypeOPEN RS 2RS RZ 2RZ Z ZZ Material of CageNylon, Steel, BrassPacking Poly bag, box, carton, plywood. ...