Set of 10 Ball Bearings 6903ZZ 17mm x 30mm x 7mm Set of 10 6903ZZ shielded ball bearings , Bearing inner diameter is 17mm, Bearing outer diameter is 30mm and Bearing width is 7mm, each bearing has 2 metal shields to protect the bearing from dust or any possible contamination, Bearings are made of Chrome Steel, also bearings are pre-lubricated with grease, Bearings are packed 10 bearings in one plastic tube.