Features1Aluminum Alloy: Bicycle headset is made of high strength aluminum alloy material, rust proof, strong and durable, fine processing to ensure a smooth surface. 2Double Bearing Structure: The double bearing structure is smoother than loose ball bearings, easy to maintain, and the handlebars are light and smooth to rotate. 3Rotate Freely: Bike headset can prevent the bearing from excessive wear and make it rotate freely. The lid is good for dust and water resistance to extend durability. 4Low Grade Opening Design: Low grade opening design, convenient for installation, disassembly and maintenance, long lastting use. 5Product Size: Diameter of upper and lower bearing is 41.8x52mm/1.6x2.0in, inner diameter of front fork lower gear is 30/39.8MM.SpecificationItem Type: Bicycle HeadsetProduct Material: Aluminum AlloyColor: As Pictures ShownWeight: Approx. 110g / 3.9ozInstallation: Low Grade Opening Design, Convenient for Installation, Disassembly and MaintenanceDiameter of Upper and Lower Bearing: Approx. 41.8x52mm / 1.6x2.0inInner Diameter of Front Fork Lower Gear: 30mm / 1.2in, 39.8mm / 1.6inPackage List2 x Bearing1 x Star Headset Cover Set1 x Headset Upper Cover2 x Front Fork Low Gear1 x PressingRing2 x Washer