6806-2RS Sealed Full Ceramic Ball Bearing Si3N4 Silicon Nitride 30mm x 42mm x 7mm 6806-2RS Full Ceramic Sealed Bearing, 6806-2RS Bearing is made of Si3N4 Ceramic and closed with Rubber Seals closure, Bearing inner diameter is 30mm, Bearing outer diameter is 42mm and Bearing width is 7mm.