Smartwool Trekking Heavy Crew Socks Heavy Cushion: Heavy cushioning offering significant impact absorption for extended backcountry excursions Sizing clearly indicated on the sock - Flat knit toe seam Elasticized arch brace - Sock Height: Crew Knit in USA of Imported Yarn: 70% Merino Wool, 29% Nylon, 1% Elastane Style: SW0SW131