6802 Full Ceramic Ball Bearing Silicon Nitride with 14 Si3N4 Ceramic Balls 15mm x 24mm x 5mm 6802 Full Ceramic Ball Bearing, bearing is Silicon Nitride with 14 Si3N4 Ceramic Balls.the inner diameter is 15mm, outer diameter is 24mm and the width is 5mm, this is a popular size that could be used in many applications.