MILITARY WATERPROOF MATERIAL: Our roof top bag is made of military grade material and heavy duty coated tarpaulin with Welded Dual Seam, Urethane COATED ZIPPERS and HOOK&LOOP CLOSURE located on flap,featuring a custom PVC inner coating for all-around WATERPROOF PROTECTION, UV proof. Triple-layer waterproof tarpaulin design makes it no leakas described. This car rooftop bag will keep your all luggage dry in weathers rain, wind, grit, or heat during your road trip or adventure vacation. UNIVERSAL FIT: Perfect car top cargo carriers FOR All sized cars,vans or SUV. WITH or WITHOUT RACKS, side rails and crossbars, basket. Our rooftop cargo bag come with 6 heavy duty straps, two of 3.6m and two of 3.9m are using for car with racks, another two of 4.2m use for car without racks. It can be quickly and easily installed in minutes with 2 ergonomic handles whether your vehicle has a rack installed or not. WAY OF HASHTAG-SHAPED TIE-DOWNS SECURES THE BAG FROM SHIFTING. Alongside carrying capacity and waterproof, Stability is arguably the most important factor of a Car Rooftop Carrier. Compared with other roof cargo carriers which are simply secured by tying four straps from 4 edge corners and 6 heavy duty straps, our roof bags are safer. LARGE STORAGE SPACE（20 Cubic Feet）：This car roofbag, which features a whopping volume of 20 cubic feet, is definitely enough to store all your luggage and gears. Dimensions are 51*39*17 inch. Pack all you want with the confidence that your luggage will stay safe and protected in all weather conditions during your trips. Great gift for Halloween, Thanksgiving Day, and Christamas. 1-YEAR WARRANTY AND LIFETIME TECHNICAL SUPPORT. If for any reason you’re not completely satisfied with our car cargo carrier for roof racks, you can feel free to contact us for a full refund by our side.