Women's Fit: Extended Backpacking, Trekking & Hiking. Endurance: Tough WoolFusion® for durable performance. Trekker: Designed for any-season, Hiking, Trekking and Backpacking. Slim Fit style designed for the regular, dedicated outdoor female enthusiast, this style ensures dry, warm and comfortable feet – mile after mile. Fibre Content: 41% New Wool 37% Nylon/polyamide 21% Endurofil™/polypropylene 1% Lycra®/elastane