Description: This premium quill stem adapter riser made of high quality aluminum alloy- sturdy, solid, high strength but lightweight Raises the height of your handlebars by increasing the height of your stem. Apply to 25.4mm to 28.6mm and 22.2mm to 28.6mm Front Fork Head Tube Converts mountain bicycle/ folding threadedless quill setup to threadless. Easy installing, operation and flexible Specification: Length: 160mm/6.3 inch Base Diameter(Upper diameter): 1 1/8'' (28.6mm) Steerer tube diameter:22.2mm/25.4mm Package Includes: 1 Piece Bike Quill Stem Adapter