Dahon SlipStream, Puro U7 aluminum, double butted tubing. Featuring patented Fusion technology, Dahon's forks integrate seamlessly with the frame and handlepost. Integrated forks use a patented coupling system to connect to the handlepost, resulting in 30% additional stiffness of the handlebar assembly. The “shoulder” on their integrated forks butts against and is supported by the wider headset when encountering directional forces. 20" wheel aluminium bikes only of the type described with 99mm headstock. Fork Supplied in Blue