So WHY are you giving this thing 4-5 stars when you say it on landing by waterproofing is emptied? Many people who like it even comment that it's not always helpful. Strange. I bought this because it folds square and fits in a backpack unlike the round crappy landing pads. BUT, 4 corners are flapping around trying to land on the grass and he almost got sucked into my quad. NOW this mat works and will NOT deflate if you place it on a flat surface. But wait. If I had a flat surface to put this landing pad on, why wouldn't I just use that flat surface to land on instead of a landing pad? Transport instead of round sprung pads that you have nowhere to put. This site is also well done. In the end I don't recommend it because it just won't stay in place and can get sucked into the quad. A: The radius of the supplied reflective stickers does not match the radius of the perimeter of the landing pad. wow again