This year we’re introducing an all-new Adaptive Fit System for the VaporAir and VaporAiress (shown above) hydration vests designed to provide the perfect fit, no matter your shape, how far you run, or how full it is. No jiggle, no bounce, no distractions. Just the perfect blend of lightweight, storage, comfort and durability.<br> The long-awaited sequels to the VaporAiress & VaporAir push the boundaries of fit and comfort, thanks to the body-hugging Adaptive-Fit adjustable sizing system. Offering an inclusive pack fit for runners of all body types, it provides comfort over the long-haul, regardless of pace, distance, terrain… or how much you sweat. Unzip the two front inside pockets to reveal hidden adjustment straps that cinch the side panels tight, for a snug, close fit that stays secure mile after mile. It’s the first-ever pack that hugs you back. As versatile as you are, The VaporAiress 2 and VaporAir 2 use the Adaptive-Fit technology to conform to your form. <br> <br>PLEASE SEE PICTURES FOR ALL SIZING INFORMATION