Kelty has been building external frame backpacks for more than 50 years. Over these years, Kelty has fine tuned and refined the classic Trekker design making it both simple and comfortable. This 3900 cu. in. version is designed for hikers with smaller torsos. The Trekker is hydration compatible and features a fully adjustable suspension, spindrift collar, and a sleeping bag compartment. On the trail, you don't want to be constantly digging through your pack to find a piece of gear. The Trekker's zippered pockets and access panels provide good organization and allow easy access to critical gear. The spindrift collar at the top of the pack expands, allowing you to stuff in more equipment. The Kelty Trekker's external frame design provides firm support and maximum comfort for moderate to heavy loads on good trails. However, the rigidity of the external frame can hamper flexibility for off-trail treks. At 3900 cubic inches, the Trekker is a good size for 2-3 day backpacking trips.