SFR188ZZ Stainless Steel Flanged Shielded Ball Bearing 1/4" x 1/2" x 3/16" inch One Bearing SFR188ZZ Stainless Steel Flanged Shielded Ball Bearing, Bearing is made of Stainless Steel, Bearing inner diameter is 1/4" inch, Bearing outer diameter is 1/2" inch and Bearing width is 3/16" inch.