Merino Treads are engineered for performance and supreme comfort, it is constructed with Virgin Aussie wool which can sit next to the skin and has a strong nylon outer. It has a full terry Leg providing insulation and and cushioning. The toe and heal are snug fit with no uncomfortable lump at the end of the toe providing extra support around the arch.It is flat knitted on the side reducing the bulk in the width of the shoe providing additional ventilation.It has a dense terry loop under foot providing soft cushioning with nylon along the full length of the foot. This product regulates and insulates temperature and moisture changes which prevents itchiness and shrink. Virgin Aussie wool 100% Australian 75% Aussie Wool 20% Nylon 5% Elastic Machine wash on wool cycle