Arksen Extra-Wide 21 Cubic Feet Rooftop Cargo Carrier Bag Waterproof Heavy Duty Car Roof Rack Bag For Full-Size Cars, 4 Door Hook Straps, 8 Reinforced Straps & Anti-Slip Mat, 42" x 48" x 18"

Only waterproof cargo bag I could find this size to fit my aerial crash pad (4ftx4ft). Bag itself is thick and the seam is definitely made to be waterproof, heavy material, huge overlap (almost makes it hard to flip up to unzip), sturdy zipper, strong Velcro, unfortunately mine ripped at the top corner seam after the first use on the road. Some of the straps/buckles also broke. I wish they were a little sturdier. However, I may need to get another to replace my first since this is the only bag big enough that would be waterproof if it didn't rip. I may just have to reinforce the seams and get some more heavy duty material to strap it down with now that I know these are it's weaknesses.

Do not buy! Extremely poor quality and ruined my move. The clips are flimsy plastic and every single one of them broke before I even loaded anything in the cargo bag. I tried to strap down with my own ties but it was not sturdy as the plastic loops I hooked my own straps through also broke. An extremely high likelihood this will fall off the top of your car while driving. Very dangerous do not buy. I asked for a refund but they are making me ship the product back first. I had to just throw away as it was useless and I didn't have room for it during my move.