This protective rain cover fits perfectly over your Urban21 bag to make it 100 percent waterproof. You can also store it seamlessly in the designated discrete pocket at the bottom of the backpack so you're prepared for an unexpected downpour. It's so packable and lightweight that you'll forget it's there, until you need it. Feel like dancing in the rain when the work day is done? Now you can because you won't have to worry about your laptop or tablet getting wet.