Yak Pak styles and prints we offer are developed in-house by our design team. We manufacture at our factory in El Salvador where great attention to the engineering behind every product. The Yak Pak bags are constructed of cotton twill fabric which is printed through a pigment dye process and sourced from a 4th generation, family-owned textile company. The bags are lined in Nylon satin, or when appropriate 420D nylon fabric, and typically there are adittional interior pockets for cell phones, wallets, keys etc. We use YKK brand zippers (the best zippers made) and sew our seams with durable NT45 Nylon Thread that is made in NOrth carolina. We are one of the few companies to offer a lifetime warranty on a fashion bag.