UV 50+ Folding Bill Cap with Double Flaps - Olive 100% Nylon Made of 100% Nylon. One size fits most, fitting up to 7 1/2. Crown measures 4 inches deep with adjustable strap closure, detachable flap in the back, detachable inner mesh flap. Bill measures 4 inches long, foldable bill. Flap measures 10.5 inches long and 20 inches wide.