Features: Modern, streamlined silhouette makes airplane travel easy Lash loops allow this Ruckpack 18 to connect to the Ruckpack 40 (not included) for check-and-carry convenience Rugged nylon shell and polyester lining fabric Nonfluorinated durable water repellent (DWR) 2 inclusive sizes let you pick the best fit Size Medium 34-38 Chest Nongendered, padded shoulder straps and an air-mesh back panel offer the comfort and support of a hiking pack Adjustable sternum strap provides extra stability while you're running to class or chasing a bus; sternum-strap buckle doubles as a survival whistle Waistbelt is removable when not in use Laptop/hydration sleeve 13 x 11 in. sleeve holds a 15 in. laptop or a hydration reservoir (not included) Zippered interior lid pocket helps keep you organized Easy-access side pocket with hidden zippered security pocket inside keeps travel essentials convenient and well-organized Stretch bottle pocket holds water while on the go Compression straps secure your water bottle and keep the weight of the pack close to your back for stability Discreet split-webbing daisy chain on the front of the pack lets you lash on gear Trekking-pole loops and tool keepers with squeeze locks stash away when not in use—creating a more streamlined look for travel or everyday use This item meets carry-on size restrictions for most airlines (size not to exceed 45 linear inches when adding L+W+H; this is subject to change, so check with your airline)