Byford's famous Byflex Sock is a 6 x 3 Rib Solid made of 64% Merino Wool, 35% Nylon, and 1% Lycra. Also available in Mid Calf. BY5102$16.50 Color: Black(90)Charcoal(30)Olive Heather(61)Blue Heather(426)Khaki Heather(11)Navy(40)Brown Heather(21)Banker's Grey(33)Taupe Heather(22)