Feature:1. Using metal bearings, 360° rotation, high speed, and accurate insertion of the front fork, unhindered and free.2. Made of aluminum alloy, T6 heat treatment, CNC process, light weight and constant strength; Internal full deep ditch ball bearings, efficient operation, lasting silent.3. Integral sealed bearing keeps the lubricant in the bearing, which has good dustproof effect and is suitable for harsh riding environment.4. Rubber waterproof loop, adding a layer of waterproof loop in the bowl cover, anticorrosion, waterproof and sandproof, longer service life.5. Suitable for the inner diameter of the upper tube of frame head tube is 44mm, the inner diameter of the lower tube is 50.6mm, and for the small tapered tube fork, the outer diameter of the upper end is 28.6mm and the outer diameter of the lower end is 33mm.How to Use:Product Order Description (From bottom to top, the headset is installed on the upper and lower ends of frame head tube): Bottom File‑Lower Bearing‑Lower Headset‑Upper Headset‑Upper Bearing‑Urgent Loop‑Headset Cover‑Sunflower Top Cover KitSpecification:Item Type: Bicycle HeadsetMaterial: Aluminum AlloySpecification: 44-50.6mm (Use with 1.25 Small Cone Tube Front Fork)Applicable Situation: Frame Head Tube: Upper Tube Inner Diameter 44mm, Lower Tube Inner Diameter 50.6mm. Front Fork: Upper End Outer Diameter 28.6mm, Lower End Outer Diameter 33mm.Applicable Measurement Instructions: (The same four data can be applied)The inner diameter of the u