The patented I-Beam system replaces the traditional saddle rail design with a single carbon composite beam. The benefits are a dramatic reduction in weight, 200% more foreaft adjustment, and superior strength. Dahon collaborated with Kore to develop their own custom saddles and seatposts. 33.9 x 580mm The patented I-Beam system replaces the traditional saddle rail design with a single carbon composite beam. The benefits are a dramatic reduction in weight, 200% more foreaft adjustment, and superior strength. Dahon collaborated with Kore to develop their own custom saddles and seatposts. 33.9 x 500mm Supplied in Black as shown. SADDLE IS NOT INCLUDED. NOTE THIS IS FOR JETSTREAM MODELS AND IS ONLY 500mm LONG