Feature:1. The integral can retain the lubricant within the bearing, the and waterproof effect is good, extending the service life, suitable for bad environments.2. Outer bowl is made of aluminum alloy material with T6 heat treatment and CNC machining, light weight with high strength.3. Built in deep gutter ball bearing and metal bearings, high speed, efficient operation with little noise; insert the fork accurately, bearing can rotate smoothly for 360°.4. Rubber waterproof circle with high quality rubber can add a layer of waterproof protection in bowl cover, anti corrosion, waterproof and sediment proof,having a longer service life.5. Universal type for straight and tapered fork, suitable for standard tapered tube front fork for upper outer diameter 28.6mm/1.12in, lower outer diameter 39.8mm/1.6in, standard straight tube front fork for upper outer diameter 28.6mm/1.12in, lower outer diameter 30mm/1.18in.How to Use:Product sequence description (from bottom to top, the bowl sets are respectively installed on the upper and lower ends of the frame head tube) : bottom gear( switchable between 30mm/1.18in and 39.8mm/1.6in), lower bearing, lower bowl set, upper bowl set, upper bearing, pressing ring, bowl set cover, sunflower shape top cover kit.Specification:Item Type: Bike Double Bearing HeadsetMaterial: Aluminium AlloyApplication: For Frame Head Tube: The Inner Diameter Of Upper Tube Is 44mm/1.7in