S609-2RS Sealed Ball Bearing Premium ABEC-5 Quality with Si3N4 Ceramic Balls (Silicon Nitride) 9mm x 24mm x 7mm S609-2RS Bearing is double sealed, radial and deep groove ball bearing,S609-2RS bearing is made of Stainless Steel with Ceramic Balls (Si3N4) and Stainless steel cage,S609-2RS bearing is closed with rubber seals to protect the bearing from dust or any possible contamination,S609-2RS bearings is sealed and self lubricated,the quality is set to EMQ (Premium ABEC-5 quality),S609-2RS bearings is lubricated with grease.