1 Ball Bearing SR8 ZZ 1/2" x 1 1/8" x 5/16" Stainless Steel One Stainless Steel Ball Bearings, this is a popular size that could be used in many application that uses this size 1/2" x 1 1/8" x 5/16". 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