Rugged twill medium duffle by Filson Lake green (Green) Rugged twill medium duffle by Filson Navy (Blue) RUGGED TWILL MEDIUM DUFFLE Rugged twill medium duffle by Filson Navy (Blue) Rugged twill medium duffle by Filson Navy (Blue). Our Rugged Twill Medium Duffle is made of rain resistant Rugged Twill and premium Italian cow leather to create a durable, dependable travel bag. It's designed to meet maximum airline carry on size restrictions, so you only need one bag for all of your journeys. The rustproof brass zipper and storm flap closure offer added protection from the weather, making this versatile bag great for overnight trips of all types. Interior pockets are made of dry finish Tin Cloth for added durability.