6321DDU Sealed Bearing 105x225x496321DDU Sealed Ball Bearing 105mm x 225mm x 49mm One Bearing 6321DDU Bearing is double sealed, radial and deep groove ball bearing, 6321DDU bearing is made from 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, 6321DDU is sealed and self lubricated, the quality is set to EMQ (electric motor quality) to ensure high speed 6321DDU bearing is lubricated