R1238ZZ Shielded Ball Bearing 3/8" x 3/4" x 0.196" inch One Bearing R1238ZZ Shielded Ball Bearing, the inner diameter is 3/8", outer diameter is 3/4" and the width is 0.196", this is a popular size that could be used in many applications, Bearing is made of Chrome Steel each bearing has 2 metal shields to protect the bearing from dust or any possible contamination, also bearing is pre-lubricated with grease.