R4-2RSNR Sealed Ball Bearing with Snap Ring One Bearing R4-2RSNR Sealed Ball Bearing with Snap Ring, the inner diameter is 1/4", outer diameter is 5/8" and the width is 0.196", this is a popular size that could be used in many applications, bearing has 2 Rubber Seals to protect the bearing from dust or any possible contamination, also bearing is pre-lubricated with grease.