Description: This bike headset made of aluminum alloy material, which delivers good durability and stability. This product has high precision CNC machining and fine workmanship, which is anti-deformation and colorfast. This bike headset product is suitable for 34mm bike frame head tube and it is compatible for 28.6mm straight steerer fork. Easy to install use, which is a nice replacement part for your bike. Electroplating Surface: Internal sealed bearing with its surface electroplating polishig. The sealing ring is good for keeping dust and water away to prolong service life. Specification: Material: Aluminum Alloy Size Chart: Size: Applicable frame: upper inner diameter of head tube 41.8mm, lower inner diameter 47mm Applicable front fork: upper outer diameter 28.6mm, lower outer diameter 33mm, Applicable frame: upper inner diameter of head tube 41.8mm, lower inner diameter 49mm Applicable front fork: upper outer diameter 28.6mm, lower outer diameter 33mm, Applicable frame: upper inner diameter of head tube 41.8mm, lower inner diameter 52mm Applicable front fork: upper outer diameter 28.6mm, lower outer diameter 39.8mm. Package Includes: 1 Piece Bike Headset