Northwave sonic 2 carbon road shoesthe northwave sonic 2 carbon road shoes offer increased performance on warm days designed with ventilation material to allow your feet to breathe the carbon sole is strategically aligned to this airflow system and provides increased stiffness thanks to the new blend of nylon reinforced with fiberglass the upper construction integrates a heel retention system without any external features to cut down on weight and keep them light as possible using an ergonomic