When the temperature drops, comfort yourself with the heavyweight warmth of this Smartwool Mountaineering Extra Heavy Crew 3-Pack of socks. Crew socks that sit at the calf. Sold in a three-pair pack. Smartwool fit system features ankle and arch braces the help ensure you get a secure fit. Extra heavy cushioning with cold mountain trails offers high impact absorption and warmth. Flat toe seam helps reduce chafing and provide all day comfort. Style Number: SW0133P3 74 percent Merino wool, 25 percent nylon, 1 percent elastane. Machine wash warm and tumble dry low. Made in the USA.