Premium Bearings, top Alien Head Diameter... 41 mm + 49 mm bottom size of top and bottom with a tube top 1 when combined with the top and bottom reservoir diameter fork with a 8 – 1/, 8/+ 1 – 3/Size to the corresponding integurarutaipu in one headset. Color: Black Bearing: Premium headtube I. D-ring. : 41/49 mm column size: 1 – 3/8 tapered solid top bottom 1 – 1/8", 1 – 3/8 Shis code: IS41/28.6 | is49 Average Weight: G (Set) The item color, about Size Item Color May Vary Depending on the type of display, actual product may vary slightly from the product image. This listing for the specification, improved the design of the logo, etc., may be altered. In addition, the manufacturers to reveal the answer your questions about the dimension and a personalized fit and you are not the actual product. Thanks for your understanding.