There's something to be said for having a day pack in your larger bag like when you're walking over to boulder half a mile from your base camp in the woods. The stuff sack weight Antimatter Pack stuffs down into its own pocket so it's easy to throw into a larger bag and bring along. Airy mesh straps keeps it breathable when the going gets steep, side compression straps cinch down your load, and two water bottle pouches hold the day's hydration. Adjustable Shoulder Straps . Removable Back Pad . Internal Pocket Doubles as Stuff Sack . Water Bottle Pocket . Compression Straps . Taped Seams . Seam Sealed . 100% polyurethane, 40D main body 100% nylon, 70D bag bottom and shoulder strap.