6811-2RS Sealed Ball Bearing 55mm x 72mm x 9mm 6811-2RS is double sealed, radial and deep groove ball bearing,bearing is made of Chrome Steel with chrome steel balls and steel cage,6811-2RS bearing is closed with rubber seals to protect the bearing from dust or any possible contamination,6811-2RS bearing is sealed and self lubricated,the quality is set to EMQ (electric motor quality) to ensure high speed,6811-2RS bearing is lubricated with grease.