WEATHERPROOF - The PVC material that is used for this car top carrier will resist heavy rain and snow to keep your goods dry while you drive through poor weather. USE WITH RACKS - Included are heavy duty straps to be used to carry your cargo and strap it to your roof racks safely and reliably. DIMENSIONS: 55" L x 37" W x 17" H LOCK INCLUDED - Feel safe knowing that your bag is locked when you stop at a rest area or stay overnight in a hotel. Included with each purchase is a lock that prevents the zippers from opening. EXTRA LARGE 20 CUBIC FEET - This bag is one of the largest on the market at 20CBFT of storage area which gives you the most space possible to store your cargo for your road trip. STRONGER & HIGHER QUALITY MATERIAL - Fedmax cargo carriers are made using 600GSM PVC which is a stronger material than the industry standard of 525GSM. The higher GSM makes a bag that will resist tears and last better through the elements. Fedmax also uses 1.5" Buckles instead of the industry standard 1" buckles to make sure your rooftop carrier bag rides as securely and safely as possible during your trip.