Hjc Helmet Adwatt 1.0 Glossy WhiteFeatures Ventury Dynamics: In order to achieve maximum ventilation, a technical adaptation of Bernoullis principle is applied to HJCs aerodynamically enhanced models. In motion, the rate of surface flow generally increases as it progresses towards the rear of the helmet. Through pressure differences, cool air from the frontal intake is extracted through the rear vent for internal heat dissipation, giving the cyclist optimum ventilation and perfect air