The Buffwear thingie is a great piece of kit. It also wicks sweat great and dries quickly, and makes a fair improvised dust/smoke mask. It weighs next to nothing and wads or folds down smaller than a deck of cards, making it a worthwhile addition to a BOB. About 20 bucks, with hundreds of colors and patterns available.

Google buffwear to see all the things you can use it for. Amazing!