The Thule 857 Caravan Roof Top Cargo Bag is a great way to give you and your passengers some extra elbow room on your next road trip.  With 13 cubic feet of capacity, measuring 40L x 32W x 18H inches.  There is room to fit sleeping bags, duffel bags, tents and other gear leaving your enterior more comfortable.  The bag is contructed from a non PVC 600 denier nylon.  PVC free materials are better than the environment.  The 600 denier nylon is tough to resist the harsh weather and wind.  The three quarter heavy duty zipper provides full access to load and unload gear and storm flaps cover the zipper to further enhance weather resistance. The bag easily attaches to most factory cross bars or side rails using four nylon straps that are included.  A stow bag is included to keep the bag stored when not in use.