Ball Bearings 5x10x4 Lot of 10 Bearings High Quality 10 bearings Wheel Ball Bearings for many applications, this is a popular size that could be used in many RC Cars and Trucks, or any application that uses this size 5mm x 10mm x 4mm. Bearings are made of Chrome Steel and can rotate up to 71000 rpm, each bearing has 2 metal shields to protect the bearing from dust or any possible contamination, also bearings are pre-lubricated with grease, Bearings are packed 10 bearings in one plastic tube.