Description: Made of steel/alloy material,lightweight and durable. Easy installation,convenient to use. Sealed cartridge bearings. Compatible with threadless 1 1/8'' (28.6mm) front fork. Great replacement parts for bike bicycle. Specification: Material: Steel/ Alloy Stack Height: 18mm/0.7inch Fit front fork tube diameter: 1 1/8'' (28.6mm) Fit bike frame head tube diameter: 44mm/1.7inch Cartridge Bearing Diameter:44/28.6-44/30(mm) Color:Black Package Includes: 1 Piece Bike Threadless Headset Note: Please allow slightly difference due to manual measurement. Color may be slightly different since different monitor. Thanks!