Nitto MT Column cold-forged aluminum with knurled clamp surface.Features-130mm tall, cold-forged aluminum with knurled clamp surface-For installing threadless stems on a threaded fork-Approximately 25mm rise increase if used with 1-1/8" headset spacer-Quill Insertion Diameter: 28.6mm-Steerer Clamp OD: 28.6mmItem Specifications-Quill Insertion Diameter:: 1 1/8"