10 Ball Bearings 1607ZZ, the inner diameter is .43748, outer diameter is .90626 and the width is .31252 inch, this is a popular size that could be used in many applications, Bearings are made of Chrome Steel and can rotate up to 20000 rpm, each bearing has Double Shielded to protect the bearing from dust or any possible contamination. Bearings are packed 10 bearings in one plastic tube.