RI56 ZZ Shielded Bearing 3/16" x 5/16" x 1/8" MiniatureRI56ZZ Shielded Ball Bearing 3 16" x 5 16" x 1 8" inch RI56ZZ Shielded Ball Bearing, a standard bearing size commonly used in a variety of industrial and commercial applications, measures an inner diameter of 3 16" inch, outer diameter is 5 16" inch and the width is 1 8" inch, each Comes with double metal shields (ZZ) to keep out dust and dirt, plus its pre lubricated with grease so its ready to roll right away. RI56ZZ Ball Bearing Deep Groove Ball