S61803-2RS Sealed Ball Bearing Premium ABEC-5 Quality with Si3N4 Ceramic Balls (Silicon Nitride) 17 x 26 x 5 mm S61803-2RS Sealed Ball Bearing is double sealed, radial and deep groove ball bearing,S61803-2RS bearing is made of Stainless Steel with Ceramic Balls (Si3N4) and Stainless steel cage,S61803-2RS is closed with rubber seals to protect the bearing from dust or any possible contamination,bearing is sealed and self lubricated,the quality is set to EMQ (Premium ABEC-5 quality) to ensure high speed,S61803-2RS bearing is lubricated with grease.