Filson's new Weatherproof bags are made with a proprietary leather that’s vegetable-tanned by Wickett & Craig, the 150-year-old Pennsylvania tannery that makes their Bridle Leather. Filson worked with this longtime partner to develop this special boot-grade leather that is weather- and salt water-resistant, then added solid brass hardware and felt-lined shoulder straps so that the bag on your back is as tough as the boots on your feet. Modeled after our most popular briefcase, this bag features a wool-felt shoulder strap for comfort and security and two internal dividers to keep tools and electronics separate. Filson Sierra Brown Weatherproof Original Briefcase 70394