S6806-2RS Sealed ABEC-5 Ball Bearing With Si3N4 Ceramic Balls 30mm x 42mm x 7mm S6806-2RS Sealed ABEC-5 Ball Bearing With Si3N4 Ceramic Balls, Bearing is made of Stainless Steel with Ceramic Balls (Si3N4) and Nylon cage, S6806-2RS bearing is closed with rubber seals to protect the bearing from dust or any possible contamination, S6806-2RS bearing is sealed and self lubricated, The quality is set to EMQ (ABEC-5 quality) to ensure high speed, S6806-2RS bearing is lubricated with grease.