Features: Craft from high strength carbon fibers for unmatch durability and stiffness. Feature a innovative expansion cores designs that ensures a secure connection to enhances safety. Experience the pinnacles of cycling performances with our light weight bicycles expansion cores set. Designs for cycling enthusiasts, road cyclists, and mountain biking aficionados. Our bicycles expansion cores set is engineered to elevates your ridings experience. Specifications: Materials: 6061Aluminum Alloys+Steel Color: As The Picture Shows Styles Optional: 6 Styles are Available as Shown in the Picture. Size: As The Picture Shows Note: Please allow 1-2cm error due to manual measurement. Please make surer you not mind before your bid. Due to the differences between different monitors, the picture may not reflect the actual color to the item. Thanks! Package includes: 1 Set of Bikes Headset Expander Stem