Byford's Byflex King Size Sock is a 6 x 3 Rib Solid made of 65% Merino Wool, 35% Nylon, and 1% Lycra. King Size Byflex fits shoe size 13 - 16. Also available in Over the Calf. Byford Byflex Mid Calf King Size 5107$17.00 Colors: Brown(21)Charcoal)30)Navy(40)Black(90)