1623-2RS Sealed Ball Bearing 5/8" x 1 3/8" x 7/16" inch 1623-2RS Sealed Ball Bearing, bearing is made of Chrome Steel with chrome steel balls and steel cage, 1623-2RS bearing is closed with rubber seals to protect the bearing from dust or any possible contamination, bearing is sealed and self lubricated, the quality is set to EMQ (electric motor quality) to ensure high speed, 1623-2RS bearing is lubricated with grease.