15 cubic feet - Designed to solve the problem of limited storage space in your car. Dimensions of the roof bag are 41in * 36in *17in. Larger capacity than most brands. Easily carry around 4-6 people's luggage! Equipped with 4 door hooks and extra 2 long adjustable straps, the Sailnovo roof bag can be used on any size car or SUV, with or without a roof rack. Easy to operate and install in a short time! Military Grade Waterproof and Tear Resistant Material! Never been used!