It's made of a rain-resistant rugged twill (and bridle leather) to create a durable, dependable travel bag. It will meet maximum airline carry-on size restrictions, so you only need one bag for all of your journeys. But it's also perfect as an overnight or weekender bag. The rustproof brass zipper and storm-flap closure offer added protection from the weather. Interior pockets are made of dry finish Tin Cloth for added durability. Solid brass zipper closure custom cut at Filson with storm flap for added security.