Feature:1. Manufacturing Material: Made of high quality aluminum alloy material, light weight, not easy to deformation, and long service life.2. Gliding and Unimpeded: The upper and lower double bearing structure of the bowl group, gliding and unimpeded, labor saving and easy protection.3. Dustproof and Waterproof: The cover is good for dustproof and waterproof to extend its durability. design, beautiful and generous.4. Applicability: The bowl set includes two types of bottom guard, which can support standard taper tube front fork and straight tube front fork.5. Product Size: The diameter of the upper bearing is 42mm / 1.7in and the diameter of the lower bearing is 52mm / 2.0in.Specification:Item Type: Bicycle HeadsetWeight: Approx.110g / 3.9ozMaterial: Aluminum AlloyApplicability: Bowl Set Includes Two Types Of Bottom Guard, Which Can Support Standard Taper Tube Front Fork And Straight Tube Front Fork.Upper Bearing Diameter: Approx.42mm / 1.7inLower Bearing Diameter: Approx.52mm / 2.0in Package List:2 x Bearing 1 x Star Nut Bowl Cover Set 1 x Bowl Group Top Cover 2 x Front Fork Bottom Guard1 x Reducing Sleeve