Feature:1. The outer headset is made of aluminum alloy, made by T6 heat treatment and CNC process, with light weight and unchanged strength. Built in ditch ball bearing, efficient operation, lasting silence.2. Metal bearing 360° rotation, high accuracy, high speed, insert the fork accurately, unhindered and free.3. Integral sealed bearing, can effectively prolong the service life, the lubricant is retained in the bearing, dustproof and waterproof effect is good, suitable for harsh riding environment.4. Rubber waterproof circle, choose high quality rubber material, adding a layer of waterproof circle in the headset cover, anti corrosion, waterproof, silt prevention and durable.5. The bicycle headset is suitable for frame head tube with the inner diameter of the upper pipe 34mm / 1.3in, the inner diameter of the lower pipe 34mm / 1.3in, the outer diameter of the upper end of the front fork of the standard straight pipe is 28.6mm / 1.1in, and the outer diameter of the lower end is 30mm / 1.2in.How to Use:Product order description (from bottom to top, the headsets are respectively 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 Double Bearing HeadsetWeight: Approx.125g / 4.4ozMaterial: Aluminum AlloySpecifications: 34-34mm / 1.3-1.3in (With 28.6mm / 1.1in Straight Fork)Applicability: The Inner Diameter Of The Upper Tube Of Frame Head Tube Is 34mm / 1.3in And The Inner Diameter Of The Lower Tube Is 34mm / 1.3in. The Outer Diameter Of The Upper End