10pcs Bicycle Headset Ball Bearings with 20 Ball Bearings for Mountain Bikes, Fixed Gear, Crankset

Outer diameter: 40 mm/1.57 inches, ball diameter: 4 mm/0.15 inches. Please confirm that the size matches your bicycle frame bearings before purchasing. Widely used: Suitable for mountain bikes and fixed-gear bikes. Function: This ball bearing features an embedded retaining device design and is a bicycle part. Used to replace the bicycle crank bearing. Material: Made of metal, strong and durable, it can be used for a long time. What you get: You will receive 10 bicycle front fork ball bearings to meet your daily needs.