S6900 Open Ball Bearing Premium ABEC-5 Quality with Si3N4 Ceramic Balls (Silicon Nitride) 10mm x 22mm x 6mm S6900 Open Stainless Steel, radial and deep groove ball bearing,bearing is made of Stainless Steel with Ceramic Balls (Si3N4) and Stainless steel cage,the quality is set to EMQ (Premium ABEC-5 quality) to ensure high speed, inner diameter is 10mm, outer diameter is 22mm and width is 6mm.