The Smartwool Light Crew Hiking Sock is a lighter version of the Smartwool Medium Crew. It shares the same solid construction, loose fit, and relative warmth. Being thinner it can handle warm weather better and can fit a liner to help with warmth and comfort.  The Smartwool Light crew performs well in chilly to cold conditions. The Smartwool Light Crew is best suited for hiking, trekking, or backpacking in these temperatures.An arch brace holds the sock in place and adds additional support, while a flat-knit toe seam keeps you comfortable throughout the day. Perfect for moderate hiking or aggressive walking.Knit in USA of Imported Yarn: 76% Merino Wool, 23% Nylon, 1% Elastane WOW™ Technology in reinforced sole for maximum comfort and durability 3x1 ribbed leg 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 Light Crew Hiking Sock