Shield Expandable Backpack

 The Shield backpack features a water-resistant main compartment which can be used in either "roll-top" mode, or in the traditional "flap-down" configuration.

The main feature is its ability to quickly double in size from 22L to 44L  when needed for extra cargo carrying capacity.

The Shield backpack also features three large and 1 small weatherproof compartments, water resistant zippers, waterproof materials, and a reinforced internal frame suspension system. Front zippered pocket fits most 15in laptop computers or any tablet, a 17in laptop can fit in the rear rolltop compartment.

An external front stretch mesh compartment holds most water bottles for those long hikes or any sporting event. Inside there is large mesh bag to hold that ball or any wet or used clothes. It has attached to an outer clip to hang free on the outside. 

Reflective taping and logos so its easy to see in the dark when light shine on it.