DZS ELEC 4pcs 3/16" x 7 Balls Bike Ball Bearing Mountain Bike Parts Repair Accessories Outer Diameter 20mm, SilverProduct Name: Bicycle Ball Bearing Material: Steel Color: silver Size: Outer diameter: 20mm (0.8 inch), inner diameter: 12mm (0.5 inch), ball diameter: 5mm (3/16 inch) Suitable for: Ordinary bicycles, mountain bicycles, mongoose bicycl..