The all-new 40-Series is the work-horse of Cane Creek's headset line-up. The series incorporates all the features necessary for a durable, light-weight, long-lasting headset and represents the perfect balance of performance, durability and value. This is a lower headset assembly 6061 T-6 Aluminum cups High quality, low friction face-seals Durable steel crown races Dependable black-oxide, sealed bearings Approximate weight 88 grams Fits Zero Stack headtubes(ZS) | Cane Creek | 40 Zerostack Lower Headset | Black | 1. 5", Zs56/40