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、Integral sealed bearing keeps the lubricant in the bearing, dustproof and waterproof, prolongs the service life, suitable for harsh riding environments. 4、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. 5、The universal version of the straight tube and tapered tube of the bicycle headset, suitable for the inner diameter of the upper tube of the frame head tube is 41.8mm/1.4in, and the inner diameter of the lower tube is 52mm/2.0in. 6、The outer diameter of the upper end of the standard tapered tube is 28.6mm 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. Specification Item Type: Bicycle Double Bearing Headset Material: Aluminum Alloy Specification: Approx. 41.8-52mm/1.6-2.0in (Straight Tube and Tapered Tube Universal) Applicable Situation: Frame Head Tube: Upper Tube Inner Diameter 41.8mm/1.6in, Lower Tube Inner Diameter 52mm/2.0in. 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 Bearing 1 x Lower Bearing 1 x 30mm Bottom File 1 x 39.8mm Bottom File