The Mechanism Thermal Long Sleeve Jersey has been tailoredremain highly aerodynamic by anatomically fitting to your riding position on the bike.The chest and frontal arm panels are constructed entirely from Swiss-made wind and water repellent Schoeller fabrics. The back panel is kept soft and highly breathable with M.I.T.I SuperRoubaix fleece. These panels have also been DWR treated for increased hydrophobic properties in order to prevent moisture absorption.