The Supermarine Rollie is a very useful product made out of some pretty fascinating material – Submarine Cotton. This high quality, very densely woven cotton was first used in World War II by the pilots in case they were shot down and stranded in the ocean because it’s extremely breathable, highly water resistant and completely windproof. The tight weave swells up when wet therefore sealing up when exposed to water. While not mainstream mostly because the price of the fabric, it’s still used by a few Air Force units, Antarctic explorers and bird watchers. By making the rollie bag out of this cotton, it allows the bag to hold your wet and/or sweaty clothes so you don’t get anything else wet but also allows whatever you have in it to dry whereas not to get all gross and mildew-y. With the top rolled 3 times, there is 10 liters of space inside. This really is great gear that will get quite a bit of use, plus it’s oddly fun to talk about the material. You can get one in black or olive colors for $88.