The k edge is cnc machined from 6061 t6 aluminium for durability and a clean mechanical finish that integrates with all high end gruppos the k edge is also perfect for anyone who likes to keep their chain in place improve shifting performance and protect their frame from damage caused by a derailed chain the original one off k edge prototype was used in kristin armstrong39s 2008 gold medal ride it attracted enough attention from the pro cycling world that the new production k edge debuted