Super-smooth steering, quality materials, cutting-edge design and serious durability are all hallmarks of Cane Creek's 40-Series headsets. - Technical Description: EC49/40/H12/K - Bottom Type: EC - External Cup - Bottom Head Tube Inside Dia.: 49.61mm - Crown Race Seat Dia.: 39.79mm - Crown Race Type: Steel, Face-Sealed - Bottom Stack Height: 12mm - Bottom Bearing Type: Black Oxide, Sealed - Material: 6061 aluminum - Weight: 76g