The Smartwool Medium Crew Hiking Sock is a sturdy, well-constructed sock that can accommodate a liner. This all-purpose sock was designed for rugged day hikes or moderate backpacking. An arch brace holds the sock in place and adds additional support. A flat-knit toe seam keeps you comfortable. It is at its best during moderately vigorous activities in cold weather. Winter travel, non-technical mountaineering, and fall/spring hiking and backpacking are all great applications. They also handle water well, so kayaking, canoe tripping, and canyoneering would also be appropriate. FeaturesKnit in USA of Imported Yarn: 74% Merino Wool, 25% Nylon, 1% Elastane WOW™ Technology in reinforced sole for maximum comfort and durability 3x1 ribbed cuff Sizing clearly indicated on the sock Flat knit toe seam Elasticized arch brace Sizing Chart (shoe size reference) Sizes US Men US Women Euro UK Small 3-5.5 4-6.5 34-37 2-4.5 Medium 6-8.5 7-9.5 38-41 5-7.5 Large 9-11.5 10-12.5 42-45 8-10.5 X Large 12-14.5 N/A 46-49 11-13.5 Smartwool Medium Crew Hiking Sock