Is built with water resistant ballistic nylon. There are two main compartments 1-padded compartment that holds a 19 in. laptop, the other has enough room to store your books, binders,files and folders and also contains pen loops and cardholders. This backpack also has aSpine Saver shoulder pad shock absorber and a back airflow system and a back strap that enables the backpack to slip over the handle of your wheeled luggage.