Dirty dog have fitted these goggles with chromolex lenses that have been treated with a specially developed anti fog coating so these goggles will give you maximum clarity in the harshest conditionsbut 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 visionthe dirty dogcvaft ventilation system uses carefully chosen areas for the intake and exhaust of cool