With two loading options and an ultra-adjustable suspension, the REI Mars pack handles extended backpacking in any season. Dual access to pack: top-loading and horseshoe-zipper front panel opening, like a duffel, gives complete view of contents. With a rip-and-stick torso adjustment, the shoulder strap system easily slides on packs frame to fit torsos of varying lengths. Removable top lid pocket lets you stash essentials to bring into your tent, so pack can stay outside or in vestibule. Zippered pocket under lid stores maps and keys, spare batteries and other small essentials. Front panel features an oversized zippered pocket protected with a waterproof zipper for storing often-used gear. EVA Soft Edge shoulder straps place seams away from your body cushioned edges provide nonbinding comfort. Durable molded foam backpanel circulates air through channels the increased ventilation keeps back cool and dry. Precurved waistbelt with a Delrin hoop cradles hip bones for a natural fit and distributes pack weight without sagging. V-pull waistbelt allows you to use a natural forward pulling motion for quick, easy cinching and precise adjustment. Internal compartment with zippered divider separates sleeping bag from gear and clothes in the main compartment. Utilizing four buckles, the packs streamlined compression system lets you cinch and strap down loads for jostle-free carrying. Concave head pod at the top of pack gives your head freedom of movement-no more staring at the ground. External mesh side pockets hold water bottles, energy bars and other essentials you want close at hand. Behind each mesh side pocket is a zippered accessory pocket for keeping gloves, hat or energy gels. Hydration-compatible design features an internal reservoir sleeve and dual exit ports for drinking tube reservoir sold separately. Special buy.