Thule's rooftop boxes significantly increase the carrying capacity of any vehicle. They include quick-mount Thule hardware and fit on Thule crossbars (sold separately), and most after-market and factory-installed racks. They're also aerodynamic to minimize drag and boost your mileage. And they're made of impact- and scratch-resistant ABS plastic for the ultimate in durability. Thule's Ascent 1600 model boasts 16 cubic feet of capacity, dual-side openings that let you access your gear from both sides of your vehicle, and also a lock to safeguard your gear.