The Zoom Q-2 Stem Quill Adapter is cold forged and allows a 23mm height adjustment. This model adapts a 1" threaded fork to a 1-1/8" threadless stem. Features: Cold-forged aluminum, 23mm height adjustment Steerer Clamp OD 28.6mm (1-1/8") For installing threadless stems on a threaded fork Quill Insertion Diameter: 22.2mm for 1" threaded forks Specifications: Fork Insertion Quill Diameter: 22.2mm Stem Clamp Diameter: 1-1/8"