So you chose the Nano fanny pack. We commend you for your ability to restrain yourself from carrying too much gear (sissy). This pack represents the cutting edge when it comes to messing with gravity's head. Its thin and rides close to your body so you will never experience any sagging or shifting. The Nano also has the new Airtrack suspension which will keep you cool and comfortable all day. If you look closely at the foam, its perforated allowing air to freely transfer between you and the pack.