Product Description Intended Use: Week-plus backpacking, Lightweight backpacking Amazon.com Pack everything you need for a weekend-plus trip to the mountains or high desert with the Sierra Revival 50 backpack. The Revival 50--which holds up to 3,100 cubic inches of gear (medium/large size)--is equipped with a comfortable Fulcrum suspension system, which includes die-cut foam shoulder straps with mesh panels and a thermo-molded, pre-curved waist belt. In conjunction with the load-lifter/stabilizer straps, the Fulcrum system distributes the weight evenly across the body, so you'll feel comfortable throughout your hike. Storage-wise, the Revival 50 includes a large top-loading main compartment, a Super-Size-Me front pocket for accessories, hip-belt Snap-or-Snack pockets, and a security pocket with a key clip. To keep you hydrated while on the trail, the Revival 50 includes a hydration sleeve (reservoir sold separately) and a pair of BPA-free water bottle pockets. The pack even comes with an integrated bottle opener, so you can pop open a soda or beer when you sit down for your well-deserved rest. In addition to carrying gear in the pockets, the Revival 50 hauls trekking poles via the pole loops and a radio or GPS via the attachment points. And the pack keeps you from overheating on hot days thanks to the ventilation conduit and ventilation detailing on the lumbar pad. Other features include a sternum strap, hip-belt stabilizers, a forward-pull waist-belt adjustment, a single DAC aluminum stay, side compression straps, a load compression strap, a storm collar, lash tabs, and a haul handle. Small/Medium Specifications: Volume: 2,950 cubic inches/50 liters Torso fit range: 16 to 18.5 inches Weight: 3 pounds 10 ounces Load capacity: 50 pounds Dimensions: 13 by 30 by 14 inches (W x H x D) Medium/Large Specifications: Volume: 3,100 cubic inches/50 liters Torso fit range: 18 to 20.5 inches Weight: 3 pounds 12 ounces Load capacity: 50 pounds Dimensions: 13 by 31 by 14 inches (W x H x D) About Sierra Designs Sierra Designs has been one of the most renowned outdoor brands in the industry since 1965. Not only are Sierra's products reliable enough to help thrill seekers like Eric Larsen summit Mt. Everest and journey to both the North and South Poles, but they promote a harmonious relationship with the environment we play in as well. The editors of Outside Magazine, National Geographic, and Backpacker Magazine have all presented Sierra with numerous gear awards. Sierra is headquartered in Boulder, Colorado.