American Flag 3ft x 5ft-The most durable American flag on the market !! Spun Polyester is the most durable American flag on the market. The open weave reduces fabric stress and resists high winds. These flags are the best choice if you fly the flag 24/7 and your wind speed is higher. As these flags are made from heavier fabric they require a higher wind speed to “fly” than nylon flags. Also they require more effort to put up and take dow.