1635-2RS Sealed Ball Bearing 3/4" x 1 3/4"" x 1/2" inch 1635-2RS Sealed Ball Bearing is double sealed, radial and deep groove ball bearing,1635-2RS bearing is made of Chrome Steel with chrome steel balls and steel cage,1635-2RS bearing is closed with rubber seals to protect the bearing from dust or any possible contamination,1635-2RS bearing is sealed and self lubricated,the quality is set to EMQ (electric motor quality) to ensure high speed,1635-2RS bearing is lubricated with grease.