R168ZZ Shielded Ball Bearings 1/4" x 3/8" x 1/8" inch Lot of 50 Bearings R168ZZ Shielded Ball Bearings, Bearings are Metal, this is a popular size that could be used in many Radio Control Cars and trucks and applications that uses this size 1/4" x 3/8" x 1/8" inch, 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, Bearings are packed 10 bearings in one plastic tube.