Features: Make Sure the Right Parameters are in Place: If your frame head tube is common for road and high end mountain, and you want to use a normal straight tube fork, or a standard tapered tube fork, then this headset is what you are looking for. Premium Quality Rubber Material: The bicycle bearing headset is made of high quality rubber, with a layer of waterproof ring on the bowl cover, which is anti-corrosion, waterproof and sandproof, making the bowl set last longer. Light and Smooth: Equipped with double bearings, smoother and easier to maintain than loose ball bearings, the handlebars rotate lightly and smoothly. Excellent Aluminum Alloy Material: Using heat-treated high-strength aluminum alloy material, process processing, light weight, strength is not reduced. Applicable Range: The lower bowl diameter is applicable to the frame with standard tapered tube fork at the lower end of the head tube inside diameter. Specification: Material: AL6061 Aluminum Alloy Size: 41.8-52mm Headset Washer Color: Black Type C: Frame head tube diameter: 41.8-52mm For fork: 1.5\" tapered fork Bearing angle: 45 degree OD*ID*Thickness: 51*39.8*5 Open / Close: close Weight: 6g Type D Frame head tube diameter: 41.8-52mm For fork: 28.6mm straight fork Bearing angle: 45 degree OD*ID*Thickness: 51*30*5 Open / Close: close Weight: 12.6g Note: 1.Please allow 1-3 cm error due to the manual measurement. Thanks for your understanding. 2.Due to the different display and different light, the picture may not reflect the actual color of the item. Thanks for your understanding Include: 1*Headset Bearing