With the aggressive PT I've been getting, I wasn't up to carrying a tight pack on my shoulders. So I decided to try something different. I bought a LuxuryLite StackPack. I walked more upright than I have in years, had almost zero weight on my shoulders the entire hike, and could get a nice breeze across my back. I look forward to using it in the near future, and testing the claims of "light, tough, and waterproof. You can float this pack across a lake and nothing gets wet."