ATX Felt Letters on our 'Field Trip™' hat. This is our most popular hat style with its 5 panel unstructured crown. Its build is derived from our nostalgia for vintage workwear hats. The timeless hats are made of brushed cotton twill fabric and feature a fabric strap with brass metal clasp. Brushed Cotton Twill Fabric Fabric Strap with Brass Metal Closure. One Size Fits All Black Imported.