Feature: 1. The integral seal can retain the lubricant within the bearing, the dust proof and rainproof 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 operating with little noise; insert the fork accurately, bearing can rotate smoothly for 360°. 4. Rubber rainproof circle with premium rubber can add a layer of rainproof protection in bowl cover, erosion proof, rainproof 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. Specification: Item Type: Bike Double Bearing Headset Material: Aluminium Alloy Application: For Frame Head Tube: The Inner Diameter Of Upper Tube Is 44mm/1.7in and Inner Diameter Of The Lower Tube Is 55mm/2.2in. For Front Fork: Standard Tapered Tube Front Fork Upper Outer Diameter 28.6mm/1.12in, Lower Outer Diameter 39.8mm/1.6in, Standard Straight Tube Front Fork Upper Outer Diameter 28.6mm/1.12in, Lower Outer Diameter 30mm/1.18in Weight: Approx.141g/4.97oz Specification: 44-55mm/1.7-2.2in (Universal Type for Straight and Tapered Fork). Package List: 1 x Sunflower Shape Top Cover Kit1 x Headset Cover1 x Pressing Ring1 x Upper Bearing1 x Upper Bowl Set1 x Lower Bowl Set1 x Lower Bearing1 x 30mm/1.18in Bottom Gear1 x 39.8mm/1.6in Bottom Gear