UC205 Full Ceramic Mounted Bearings 25mm x 52mm x 17mm (inner race width= 34.1mm) Full ceramic UC205 25mm mounted Bearing, the inner diameter is 25mm, outer diameter is 52mm and the width of the inner race is 34.1mm, the width of the outer race=17mm, this is a popular size that could be used in many applications, Bearing is made of Ceramic.