Excellent features like our 4th dimension cooling system and patented clip on visor plus certified protection and sleek styling make the chamonix a terrific value for any cyclistone size system designed for easy and accurate fit to a wide range of head sizesheadset sx fit system with micro adjustable dial for easy secure and accurate fit4th dimension cooling system optimizes ventilationin moulded shell improves strength and reduces weighttri fix web splitter for improved comfort and ease of