SR1038ZZ High Speed Ball Bearings Stainless Steel ABEC-5 7 Solid SI3N4 Ceramic Balls 3/8" x 5/8" x 5/32" inch SR1038ZZ ABEC-5 High Speed Ball Bearing, bearing is Stainless Steel bearings with 7 solid SI3N4 Ceramic Balls, Bearing is made of Stainless Steel and has Solid Ceramic balls (SI3N4).