5 x 8 x 2.5 Shielded Ball Bearings 10 Ball Bearings 5 x 8 x 2.5 Shielded Ball Bearings, this is a popular size that could be used in many RC Cars and Trucks or any application, Bearings are made of Chrome Steel, each bearing has 2 metal shields to protect the bearing from dust or any possible contamination, also bearings are pre-lubricated with grease.