1621-2RS Sealed Ball Bearing is radial, deep groove ball bearing,1621-2RS bearing is made of Chrome Steel with chrome steel balls and steel cage,bearing is closed with rubber seals to protect the bearing from dust or any possible contamination,1621-2RS bearing is sealed and self lubricated,the quality is set to EMQ (electric motor quality) to ensure high speed,1621-2RS bearing is lubricated with grease.