I had previously bought the Arc'Teryx Mantis 1 for travel and for days where I wasn't wearing full jeans or cargo shorts with plenty of pockets. But when I loaded it up with my wallet, phone, keys, Leatherman, bluetooth earbud case, and sunglasses/reading glasses, it was pretty well stuffed and made it hard to access items. It also was pretty fat. The mantis 2 is more generous and allows me to carry all those, plus maybe my passport, Dramamine, and a pack of gum without looking overstuffed. The adjustable strap allows a multitude of wearing positions, although I wouldn't advise strapping it to you head or neck. Escape Outdoors, thank you for quick and easy delivery.