UPGRADED MATERIAL: Compared with the basic version, the upgraded version keep the design,appreance and function, only change the materials from Polyster(front) + Oxford(side)+to Microfiber(front+Polyseterside). It looks more beautiful and higer level. Besides, with Microfiber material, the waterproof level is much higher. SEPARATED LAPTOP COMPARTMENT FOR 15.6 INCH: Bange Backpack has a separated 15.6 Inch laptop compartment. The thickening sponge can well protect your notebook. The TSA lock can prevent your laptop from stealing. ANTI THEFT BACKPACK: The computer backpack is equipped with a smart secure lock that is made of high strength zinc alloy with a solid, compact body to prevent theft and well safeguard all your valuables securely. The password lock is easy to set (Includes instructions), please see A+ for the detailed instruction. LIGHTWEIGHT BACKPACK WITH LARGE CAPACITY: The size is 18.5in*13.7in*8.2in(H*L*W), and the weight is only 1.5lbs.The capacity is around 32L, a