Features1If your frame head tube has an inner diameter of 4252mm / 1.62in (common on roads and highend mountains), and you want to use a 28.6mm / 1.1in ordinary straight tube front fork, or a standard cone tube 1.5in front fork, then this headset is what you are looking for 2Use highquality rubber, add a layer of waterproof ring in the bowl cover, anticorrosion, waterproof and sandproof, so that the service life of the bowl set is longer. 3Equipped with double bearing, it is smoother and easier to maintain than loose ball bearing, and the turning of the handlebar is light and smooth. 4Using T6 heattreated highstrength aluminum alloy material, CNC process processing, the weight is light and the strength will not decrease. 5Diameter of the lower bowl is suitable for the frame with the inner diameter of the lower end of the head tube of 52mm / 2in. 6Built-in oil seal, high-efficiency waterproof, prolong life, effectively avoid installation gap problems, and install in one step. 7Open design, open bottom block, matching dual-purpose bottom block (optional), more convenient to use.SpecificationItem Type: Bike HeadsetBottomGearMaterial: Aluminum AlloyWeight: Approx. 116g / 4.1ozSpecification: 41.8 x 28.6-52 x 30 or 39.8 (Specification: 1 1/8in + 1 1/2in)Suitable for: Frame Head Tube with Upper and Lower Inner Diameters of 41.8-52mm / 1.6-2in, Used with Ordinary 28.6mm / 1.1in Straight Tube Front Fork, or Standard 1.5in Tapered Tube Front Fork (You Can Choose the Corresponding Option According To The Matching Front Fork)Package List1 x BottomGear2 x Bearing1 x Urgent Ring1 x Bowl Cover1 x Sunflower Screw Top Cover