If you get just one faceGlove, get a FLEX. The faceGlove FLEX integrates with any glasses, goggles, neck gaiter, or balaclava, securing it our most versatile face mask. Made from the best soft-shell fabrics in the world, the FLEX is thin, light, breathable, and highly wind and water-resistant. A coated, double wire allows this faceGlove to hold the correct shape around your nose to vent hot air. Simple enough for dog-walking, and cycling. Trusted by guides on Denali and Everest for 14 years. Ideal For: Winter hikers, cross country skiing, snow shoeing, cycling, and paragliding. Great for sun, wind, and cold protection. Anyone that needs a layer of protection between themselves and the elements. UPF 50+ sun protection Sizing: The easiest way to find the right size is match your helmet. So a person that wears a medium helmet should purchase a medium faceGlove FLEX. Some users also find using their height / weight as a good way to find the right size. Small - 5&';0" - 5&';3", 100 - 130lbsMedium - 5&';3" - 6&';0", 130 - 210lbsLarge - over 6&';1" and 210lbs