8 x 14 x 4 Stainless Steel Ceramic Si3N4 Ball Bearing Quality: Premium ABEC-5 One Bearing 8 x 14 x 4 Stainless Steel Ceramic Ball Bearing, bearing is made of Stainless Steel, Quality is Premium ABEC-5, bearing is rubber sealed from both sides to protect the bearing from dust or any possible contamination, also bearing is pre-lubricated with grease, the inner diameter is 8mm, the outer diameter is 14mm and the width is 4mm.