Ball Bearings 6308-2RS 40 x 90 x 23 6308-2RS Ball Bearings, the 6308RS inner diameter is 40 mm, 6308-2RS outer diameter is 90 mm and the 6308RS width is 23mm, 6308RS is a popular size that could be used in many applications, 6308RS Bearings are made of Chrome Steel,6308-2RS can rotate up to 5300 rpm,6308-2RS bearing has 2 Blue Rubber Seals to protect the bearing from dust or any possible contamination,6308-2RS bearings are pre-lubricated with grease.