One Ball Bearings 15 x 28 x 7 Stainless Steel One bearings Stainless Steel Ball Bearings, this is a popular size that could be used in many application that uses this size 15 x 28 x 7. Bearings are made of Stainless Steel, each bearing has 2 metal shields to protect the bearing from dust or any possible contamination, also bearings are pre-lubricated with grease