S607 Open Ball Bearing ABEC-7 Quality with Si3N4 Ceramic Balls (Silicon Nitride) 7mm x 19mm x 6mm S607 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 (ABEC-7 quality), inner diameter is 7mm, outer diameter is 19mm and width is 6mm.