The fulcrum of the 11 speed system. An absolute innovation. 11 speed parallelogram geometry operates with absolute precision . Silver anodized forged aluminum upper body with oversized carbon fiber composite parallelogram link, which confers 150% great torsional rigidity . Light alloy outer and inner cages with specially lightened anti-vibration pulleys for maximum smoothness. Short cage (55mm pulley-pulley axle dimensions).