The Osprey Pack's Osprey Packs Ultralight Stretch Stuff Sack is an adaptable stuff sack for holding onto the weird-shaped pieces of gear. Or just overstuffing. The special side panels stretch to fit that one thingy and stretch to fit one more t-shirt inside. Cinch the top and tuck it into your pack. Easy as pie. The Osprey Ultralight Stuff Pack does just that with deluxe features not found in most daypacks.