6404-2RS Sealed Ball Bearing 20mm x 72mm x 19mm One Bearing 6404-2RS Sealed Ball Bearing, the inner diameter is 20mm, the outer diameter is 72mm and the width is 19mm, 6404-2RS Bearing is made of Chrome Steel,bearing has 2 Rubber Seals to protect the bearing from dust or any possible contamination,6404-2RS bearing is pre-lubricated with grease.