The Voltaic Backpack™ is built tough for use as a weekend hike bag or as a large daypack. There are pockets and wire channels for multiple electronic devices and 1,850 cubic inches of storage space. Features: High density padding in the shoulder straps and back panel for comfort Nylon mesh backing material for better air flow The solar panels provide protection for fragile items inside the front pocket Wire channels throughout the bag take power to the shoulder strap and for headphones etc. Adjustable phone / MP3 pouch on the shoulder Second lined MP3 / sunglasses pouch inside Optional clip in padded laptop sleeves Bladder pouch and channels to run the tube to the shoulder strap Specifications: Fabric: 840D nylon, UV resistant PU, nylon mesh on the back Weight: 3.5 lbs (1,590 grams) including battery and solar panels Dimensions:20" high x 10-15"wide x 7-10" deep (51cm high x 25-38cm wide x 18-25cm deep) Volume: 1,850 cubic inches (30 liters) Electronics: The electronics are the same as the other three Voltaic™ solar bags. Note: It is not designed to charge laptops, it will however charge cell phones, sat phones, PDAs, GPSs, iPods, cameras etc. Includes a 2,200mAh Li-Ion battery pack with 3 voltage settings to store solar power When not in the sun, the battery can be charged using the AC travel charger or DC car charger Comes with 11 standard adaptors including a car charger socket and USB adaptor so you can always use a standard charger for your device Includes adaptor plugs in universal sizes and for common cell phones, which eliminate the need to use a car charger for common devices The three solar panels are tough, light weight, waterproof, and generate up to 4 watts of power