Features 1、The outer headsetis made of aluminum alloy, adopting T6 heat treatment, CNC technology, light weight and constant strength, built in ball bearings, efficient operation, long lasting silence. 2、The metal bearing can rotate 360°, high accuracy, high speed, and accurately fit into the front tube, smoothly and freely. 3、The headset adopts a colorful surface process, which is colored by water plating and vacuum plating. The surface hardness is strengthened, not easy to fade, and the appearance is higher. 4、Equipped with double bearing structure, which is smoother and easier to maintain than loose ball bearings, and the turning of the handlebar is light and smooth. 5、The integral sealed bearing keeps the lubricant in the bearing, has good dustproof and waterproof effect, prolongs the service life, and is suitable for harsh riding environment. 6、The rubber waterproof loop is made of high quality rubber, and a layer of waterproof loop is added to the headset cover to prevent corrosion, water, and sand, and have a longer service life. 7、The universal version of the straight tube and tapered tube of the bicycle headset is suitable for the inner diameter of the upper tube of the frame head tube is 44mm/1.7in and the inner diameter of the lower tube is 55mm/2.2in. 8、The outer diameter of the upper end of the standard and tapered tube is 28.6mm/1.1in and the outer diameter of the lower end is 39.8mm/1.6in; or the outer diameter of the upper end of the standard straight tube is 28.6mm/1.1in and the outer diameter of the lower end is 30mm/1.2in. Item Type: Bicycle Double Bearing Headset Material: Aluminum Alloy Specification: Approx. 44-55mm/1.7-2.2in (with 28.6 Straight Tube/1.5 Tapered Tube) Applicable Situation: Frame Head Tube: Upper Tube Inner Diameter 44mm/1.7in, Lower Tube Inner Diameter 55mm/2.2in. Front Tube: Upper End Outer Diameter 28.6mm/1.1in, Lower End Outer Diameter 39.8mm/1.6in. Tapered Tube: Upper End Outer Diameter 28.6mm/1.1in, Lower End Outer Diameter 30mm/1.2in. Applicable Measurement Instructions: (The Same Four Data Can Be Applied) The inner diameter of the upper tube and the inner diameter of the lower tube, to obtain the inner diameter of the upper and lower tubes of frame; The outer diameter of the upper end and the outer diameter of the lower end are the outer diameters of the upper and lower ends of the front tube. Package List 1 x Sunflower Top Cover Kit 1 x Headset Cover 1 x Urgent Loop 1 x Upper Headset with Bearing 1 x Lower Headset with Bearing 1 x 30mm Bottom File 1 x 39.8mm Bottom File