S6807 Open Ball Bearing Premium ABEC-5 Quality with Si3N4 Ceramic Balls (Silicon Nitride) 35 x 47 x 7 mm S6807 Open Ball Bearing, radial and deep groove ball bearing,bearing is made of Stainless Steel with Ceramic Balls (Si3N4) and Nylon cage,the quality is set to EMQ (Premium ABEC-5 quality) to ensure high speed,inner diameter is 35mm, outer diameter is 47mm and width is 7mm.