Feature:1. Headset outer bowl is made of high strength aluminum alloy, T6 heat treatment.2. Suitable for standard straight tube front fork with an outer diameter of 28.6mm at the upper end and 30mm at the lower end.3. CNC process, light weight and unchanged strength, sturdy, durable and long service life.4. Suitable for the inner diameter of the upper tube of head tube is 41.4mm, and the inner diameter of the lower tube is 41.4mm.5. Adopt metal ball bearing, high precise, efficient operation, accurate insert into the front fork, and free.How to Use:Product sequence description (from bottom to top, the headsets are installed on the upper and lower ends of the frame head tube): bottom gear, bearing frame, ball bearing, lower headset, upper headset, ball bearing, bearing frame, upper baffle, headset cover, headset top cover kit.Specification:Item Type: HeadsetColor: BlackMaterial: Aluminum AlloyWeight: Approx.123g/4.3ozSpecification: Approx. 41.4mm/1.6in (for Use with Approx. 28.6mm/1.1in Straight Fork)Application Situation:Frame Head Tube: the Inner Diameter of the Upper Tube: Approx. 41.4mm/1.6in, the Inner Diameter of the Lower Tube: Approx. 41.4mm/1.6inFront Fork: Standard Straight Tube Front Fork Outer Diameter at the Upper End: Approx. 28.6mm/1.1in, Outer Diameter at the Lower End: Approx. 30mm/1.2inApplicable Measurement Instructions: (the Same Four Data Can Be Applied)Inner Diameter of the Upper Tube and the Inner Diamete