This Smartwool PhD Outdoor Medium Crew 3-Pack of socks will give you the extra cushion you need for the trails ahead. Crew socks that sit at the calf. Sold as three-pair pack. 4-Degree Elite Fit System construction uses two elastics to provide better stretch and to keep your sock in place. The PhD socks are packed with technologies that are designed to keep your feet comfy so you can focus more on the trail. Medium cushioning that balances warmth and protection in colder weather. Indestructawool is engineered to provide maximum comfort and durability. Mesh panels on the out step help provide added breathability. Virtually Seamless toe is designed for all day comfort and to minimize chaffing. Style Number: SW000566 63 percent Merino wool, 35 percent nylon, 2 percent elastane. Machine wash, tumble dry. Made in the USA.