The Zipp Service Course SL Stem, crafted from 7075 aluminum, features a shape that’s strong and lightweight, resulting in a 1.85 grams per newton meter of stiffness. That results in no-flex sprints and accelerations. FEATURES: High-strength and low weight AL6061 construction Smooth lines to complement the aesthetics of modern frames Strength, stiffness, and reliability at a weight of 130 grams (100mm) New faceplace and body geometry for greater stiffness and easier installation Mounts using four Torx T25 bolt heads SPECS: Bar Diameter: 31.8mm Steerer Diameter: 1-1/8" (28.6mm) Length/Reach: 60, 70, 80, 90, 100, 110, 120, 130mm Stack Height: ?41mm Material: Aluminum Weight: 130g (100mm)