Features 1、Headset outer bowl is made of high strength aluminum alloy, T6 heat treatment. 2、Suitable for standard straight tube front fork with an outer diameter of 28.6mm at the upper end and 30mm at the lower end. 3、CNC process, light weight and unchanged strength, sturdy, durable and long service life. 4、Suitable for the inner diameter of the upper tube of the frame head tube is 41.4mm, and the inner diameter of the lower tube is 41.4mm. 5、Adopt metal ball bearing, high precise, efficient operation, accurate insert into the front fork, smooth and free. Item Type: Bicycle Headset Color: Black Material: Aluminum Alloy Weight: Approx.123g/4.3oz Specification: Approx. 41.4mm/1.6in (for Use with Approx. 28.6mm/1.1in Straight Fork) Application Situation: Frame Head Tube: the Inner Diameter of the Upper Tube: Approx. 41.4mm/1.6in, the Inner Diameter of the Lower Tube: Approx. 41.4mm/1.6in Front Fork: Standard Straight Tube Front Fork Outer Diameter at the Upper End: Approx. 28.6mm/1.1in, Outer Diameter at the Lower End: Approx. 30mm/1.2in Applicable Measurement Instructions: (the Same Four Data Can Be Applied) Inner Diameter of the Upper Tube and the Inner Diameter of the Lower Tube Are Used to Obtain the Inner Diameter of the Upper and Lower Tubes of the Frame. 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 Fork. Package List 1 x Headset Cover Kit 1 x Headset Cover 1 x Top Baffle 2 x Bearing Frame 2 x Ball Bearing 1 x Upper Headset 1 x Lower Headset 2 x Bottom Gear