Features:Anti-Freeze and Waterproof, High-density & High-quality nylon materialAnti-theft zipper, Double-layers four-teeth anti-theft zipper designReflective strip design, Safely walking or driving at night4.0 USB fast charging port, Charges up to 20% faster than standard cables and transfers data at 800Mbps via USB 2.0TSA Lock design, there isnt any key assort with the lock, the key hole is for customs inspecting to protect your backpack not be opened rudely.Large capacity design, only the extend model can be expandableErgonomic back desi