US Made Genuine GI Thermal Military Heavyweight Boot Socks Thick Nylon Cotton NYCO (3 Pack) Nylon Cotton NYCO Material Made in USA 3 Pairs of Socks Included - Choose from Black, Khaki or Olive Drab. Made in the USA. Genuine Government Issue GI Military Socks. Made from Nylon Cotton NYCO Material. One Size: Fits Mens shoe sizes 10 - 13. Thick, warm & comfortable.