Wool is king. These long, boot style socks are built to keep your feet and lower legs cozy warm and dry without starting a sweat factory in your boot. A wool inner layer, providing a perfect balance of warmth and moisture control in a wide range of conditions. The Merino Wool (black/grey) socks are 75% Merino and 25% Polyamide/Lycra. If you have issues with the ‘feel’ of wool, you should probably stick with these thinner, slightly finer Merino Wool socks. M (5.5-9.5), L (10-12.5).