Redesigned for thru hikers and long-distance backpackers, the Unbound 40 and 55 are lighter, stronger, and more comfortable thanks to an updated build with the exceptionally durable Dyneema® Woven Composite 3.9. Two contoured removable stays, a refined hip belt, and wider, more naturally curved shoulder straps improve support and comfort under heavier loads, while streamlined construction with internal seam taping and low-profile sewn-in daisy chains creates a cleaner, more functional design. A fully removable, customizable compression system makes it easier to secure trekking poles or oversized water bottles, while trail-proven features like the dual-entry front pocket, bottom pocket, V-Pull hip belt, and accessible side bottle pockets remain as intuitive and efficient as ever.