Lightweight lumbar pack with adjustable volume

　　The Sierra Designs Flex Lumbar collection takes the same expanding gusset found in the popular Flex Capacitor and shifts it vertically to work as a lumbar pack. Integrated water bottle pockets and enough room to stash a layer and some food means you have your bases covered for any day hike. Flex it open when you need to carry more, or cinch it down when you want a lower-profile pack.