6006ZZ Shielded Ball Bearings 30mm x 55mm x 13mm 6006ZZ Shielded Ball Bearings, the inner diameter is 30mm, outer diameter is 55mm and the width is 13mm, Bearings are made of Chrome Steel, each bearing has Double Shielded to protect the bearing from dust or any possible contamination. Bearings are packed 10 bearings in one plastic tube.