One Ball Bearings 6905-2RS 25 x 42 x 9 mm Set of 10 Ball Bearings 6905-2RS, the inner diameter is 25, outer diameter is 42 and the width is 9, this is a popular size that could be used in many applications, Bearings are made of Chrome Steel, each bearing has 2 rubber seals to protect the bearing from dust or any possible contamination, these are self lubricated bearings .