F688-2RS Flanged Unground Sealed Ball Bearing 8mm x 16mm x 5mm One Bearing F688-2RS Flanged Unground Sealed Ball Bearing, each F688-2RS bearing is rubber sealed from both sides to protect the bearing from dust or any possible contamination, also bearing is pre-lubricated with grease, inner diameter is 8mm, outer diameter is 16mm and width is 5mm.