6208UU Ball Bearing inner diameter is 40mm, outer diameter is 80mm and width is 18mm, Ball Bearing 6208UU is a popular size that could be used in many applications, Bearing is made of Chrome Steel and can rotate up to 40,000 rpm, each 6208UU bearing has 2 Rubber Seals to protect the bearing from dust or any possible contamination, bearing is pre-lubricated with grease.