The name speaks for itself as the most comfortable and versatile backpack we have ever worn. The "Just One" is made to go out light and come back heavy, it performs equally well as a daypack or as a heavy load freighter. Over-sized compression straps hold the load close to your body and the internal frame Flex Chasis transfers the weight to your hips. Full length side access zippers on large front pockets provide access to your gear. The J-34 "Just One" pack expands from 2300 cubic inches up to 4600 cubic inches and can be boosted all the way up to 7500 cubic inches when you add on the Super Spike Duffel. Mountain Camo pattern.