Lot of 50 Bearings R166 ZZ 3/16" x 3/8" Ball Bearings High Quality. ( Lot Of 50 ) inch size Ball Bearings, they are used in many applications, the inner diameter is 3/16", outer diameter is 3/8" and the width is 2/16", this is a popular size that could be used in many applications, each bearing has 2 metal shields to protect the bearing from dust or any possible contamination, also bearings are pre-lubricated with grease.