Developed in collaboration with trail running phenomenon Killian Jornet, 2 time winner of The North Face UTMB, Record holder in the Corsica Traverse, Lake Tahoe Rim Trail and Pyrenees Traverse, the XT Advanced Skin 5 S-Lab system stretches to form a snug, flexible fit around the shoulders and upper torso, compressing the load without any chaffing or excess movement. Made from soft, breathable stretch materials throughout the system, it distributes weight more evenly and comfortably than any pack we have previously designed. "Trail running packs require very specific expertise", explains Fabienne Richard, Salomon Product Manager for bags and packs, "We tried many different prototypes, and were able to push the limits of motion fit to a new level. We call this construction Sensifit, which really owes its design to direct input from the world's best trail runner."
In addition to the unique new motion fit construction, XT Advanced Skin 5 S-Lab incorporates a wealth of other innovative features. Replacing traditional sternum straps, the Twin Link system is fully adjustable and made from soft, stretchy material,
providing flexible adjustability and stability without limiting the runner's motion or breathing. All seams and hard materials in the pack are minimized, completely eliminating chafing and abrasion. The Source hydration bladder hose is routed through the bottom of the pack straps, reducing the hose length so drinking requires less energy. The XT Advanced Skin 5 S-Lab also securely holds a host of Salomon accessories, enabling runners to add volume, carry poles conveniently or attach more water bottles. Finally, an included safety "space blanket " doubles as padding and back insulation for the hydration bladder. But with all these features, the thing that is perhaps most striking about the XT Advanced Skin system is how light it is. There is very little material in the pack, and the material that is there is extremely light and soft. Looking at the pack, one can see it is minimal, but wearing the pack feels about like wearing an extra shirt. There is nothing excessive.
ultra running backpack. 
