S6207-2RS Sealed Ball Bearing Premium ABEC-5 Quality with Si3N4 Ceramic Balls (Silicon Nitride) 35mm x 72mm x 17mm S6207-2RS is double sealed, radial and deep groove ball bearing,S6207-2RS bearing is made of Stainless Steel with Ceramic Balls (Si3N4) and Nylon Cage,S6207-2RS bearing is closed with rubber seals to protect the bearing from dust or any possible contamination,S6207-2RS bearing is sealed and self lubricated,the quality is set to EMQ (Premium ABEC-5 quality) to ensure high speed,S6207-2RS bearings is lubricated with grease.