- 100D Nylon Ripstop/420D Nylon Oxford
- Expandable 40-60L volume (volume varies between sizes)
- Adjustable volume side pockets
- Single top access zipper
- Zippered stash pocket on lid
- Two waist-belt pockets
The flex capacitor features a unique patent pending gusset system that allows the pack to quickly and easily expand from 40-60 liters with the adjustment of a few straps. Instead of expanding up like other packs, the circumference of flex expands to provide a more stable and comfortable load carry.
Sierra Designs Flex Capacitor 40-60L Hiking Backpack – S/M Review