Heat Factory Wader Sock with Compression Fitting improves circulation, relieves leg fatigue; especially for those who sit or stand for long periods of time. Compression Fitting allows the sock to stay in one comfortable position all day and has pockets over the toes for Heat Factory warmers. Warmers not included. Contains:  50% Merino Wool, 30% acrylic, 10% nylon, 10% lycra.