The Trekking Heavy Crew Sock by Smartwool. Heavy full-cushioning provides shock absorption, offers Insulation against the elements, and supports under weighty loads. Arch brace holds the sock in place and adds additional support. Flat-knit toe seam keeps you comfortable. Features of the Smartwool Trekking Heavy Crew Sock Sizing clearly indicated on the sock Flat knit toe seam Smartwool Trekking Heavy Crew Sock Elasticized arch brace Made in USA