[Anti- and Wear ]--Adopt high grade steel material, , anti- and wear for long term use. [Waterproof & Dustproof]--Use sealing rubber ring, can effectively prevent water and dust from entering. [External Diameter]--External diameter 52MM, angle 45°, fits for your . [Universal Fit]--It is a helpful accessory for competition, mountain bikes, road , etc. [Exquisite Workmanship]--Clear printing and exquisite workmanship, reflect the of its quality, which not disappear with the number of uses. Color: As shown Material: Bearing Steel Package Contents: 2 x Bicycle Bearings Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.