The Evernote Triangle Commuter Bag exterior is made of a 65% nylon, 35% polyester fiber which is very resistant. The nylon interior helps protecting the bag contents in case you get some rain, but I wouldn’t classify it exactly as waterproof. I got through some pretty heavy rainfall in New York and São Paulo and didn’t get any water inside, but I wouldn’t abuse it. Inside, there is a 15″ laptop pouch, two smaller pouches and a larger compartment which is customizable by 3 nylon dividers which you can move around to fit your needs. When you fully open the bag, the side panel folds down and reveals two more zip-sealed pockets: one concealed, and one mesh pocket.