The Waterproof Backpack protects your laptop and other valuables by keeping the wet out with waterproof zipper closures and reinforced waterproof layer. With ergonomic, adjustable shoulder and sternum straps as well as a padded airflow back panel. This pack keeps you comfortably cool and organized. This Backpack also features an RFID blocking pocket and zippered expansion panel to increase capacity from 25L to 35L when you need it.