The Ironman Flash Pro Low-Cut Sock boasts the UltiMax Pro moisture control system to keep your feet cool, dry, and blister-free. Ultra-light X20 acrylic yields superior insulation, moisture absorption and dissipation, and natural antimicrobial properties. Mesh air vents provide maximum breathability, while the heel tab helps reduce slippage. The lightweight instep, cushioned sole, and seamless toe closure ensure long-wearing durability and comfort. The Ironman Flash Pro Sock is made from a rugged 83% stretch nylon, 16% X2O acrylic, 1% spandex fabric blend. Made in the USA.