Premium features certified protection and sleek styling make the chamonix a great 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 optimises ventilationtri fix web splitter for improved comfort and ease of strap adjustments in moulded shell improves strength and reduces weightreflective webbing and decals for added night time visibilit