Sidi ergo 4 carbon composite shoes lightweight and durable offering a custom fit for optimal support and comfortfeaturing sidis new racing sole with an additional vent which can be opened and closed on the top of the sole to provide excellent ventilationthe carbon in the sole provides a light flex to the toe area but maintains stiffness through the main body giving excellent power transferthe soft instep 3 closure system is adjustable from both sides to evenly distribute pressure over the ar