Super-smooth steering, quality materials, cutting-edge design and low weight are all hallmarks of Cane Creek's AER headsets. They have light, tough, and beautiful machined 7075 T6-aluminum cups that are contoured and relieved for even more gram shaving. In the top cup, there's a superlight Norglide composite bearing that only weighs 1.5 grams! The bottom cup features a durable Cane Creek black oxide bearing for durability. Also, a carbon-friendly captured compression ring and a dual-sealed crown race with a complete upper bearing seal keeps the grease in and the dirt out. What's more, the seals are low-friction to improve steering performance and there are no loose headset parts so maintenance is easy.