If you need a flag to fly in the mile-high climes of the Rocky Mountains, check out the 4' x 6' Superknit polyester state flag of Colorado available at United States Flag Store. Superknit polyester is a significant step up from standard polyester, and you'll notice the difference in its durability and flyability when displaying the Colorado flag outdoors. There is a nylon header for reinforcement and two brass grommets. The current blue and white flag with a red "C" surrounding a yellow ball has been in use since 1964, the year that the state legislature adopted a revised design that called for a much larger "C" than had earlier been displayed on the flag.