The PhD Ski Light Elite socks feature ndestructawool durability technology, Smartwool's dialed-in 4 Degree elite fit system, and body-mapped mesh zones for added breathability. Indestructawool technology. 4 Degree elite fit system. Contoured shin and ankle cushioning, with flat knit toe box. Length: Knee High. Weight: Light. Material: 55% Merino Wool, 42% Nylon, 3% Elastane . Machine wash. Imported.