... 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 ... .Appearance inspection 8.Rust prevention 9.Product packaging Adapter sleeve H series