Dirty Dog goggles are fitted with POLYCARBONATE lenses that have been treated with a specially developed Anti-Fog coating so these goggles will give you maximum clarity in the harshest conditions. But they have not stopped there! They have added Custom Venting Air Flow Technology (CVAFT) to give extra protection against dangerous lens fogging and giving you exceptionally clear field of vision. The DIRTY DOG (CVAFT) Ventilation System uses carefully chosen areas for the intake and exhaust of cooling air. The Dirty Dog face foam is super soft open cell technical foam designed to maximise comfort. Produced with materials tested to -20 degrees you can wear them with the confidence that they will perform as well as you will, sometimes better!