With a new 4 Degree Elite Fit System and ReliaWool technology, SmartWool PhD Cycle Ultra Light Micro Socks deliver an improved fit, more comfort, and greater durability. Ultralight-no cushion for maximum performance next to the foot. New 4 Degree Elite Fit System with bi-elastic construction across four fit bands improves fit and comfort with faster flex and recovery-four-point support at ankle, upper and lower instep, and arch to keep the sock in place. ReliaWool technology in high-impact areas provides longer lasting durability and protection to keep feet comfortable. Soft, breathable merino wool regulates temperature, manages moisture, naturally resists odor, and does not itch or shrink. Mesh ventilation zones for temperature and moisture regulation. Low-profile and durable virtually seamless toe. Alternating 1x1 welt. Overall height: 1.5 in.. Machine wash warm inside out, gentle cycle; tumble dry low.