1604-2RS Bearing is regular section, double sealed, radial and deep groove ball bearing,1604-2RS 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,1604-2RS bearing is sealed and self lubricated,the quality is set to EMQ (electric motor quality) to ensure high speed,1604-2RS bearing is lubricated with grease.