If torn between a conventional and aero road lid, this is your answer. Developed with Team Sky, the Kask Protone is an incredibly aerodynamic and top performing helmet, tested in the wind-tunnel and able to provide a really impressive efficiency. The Protone was designed to maintain aerodynamics and airflow in any common riding position, and however you move your head, it remains consistent. The diminutive dimensions belie its spaciousness. Weighing in at 251g, the Protone uses 'Octo Fit' retention offering three-way adjustment, allowing you to move the pads vertically and laterally whilst a rotary dial tightens the headband shell. The comfy eco leather chinstray keeps everything secure.