WilmasboyL78 is right!
They work great!
They keep your car dust free!
First you must dust your car off with a good clean duster.
Then cover it with a soft indoor type cover.
Then a few more cheaper car covers for insurance.
Maybe a couple of moving blankets.
Then the bag!!!
If you ordered one a little larger than you need, it will be more forgiving in the placement of the car. You will have a lot more bag to zip around it. If the bag is a snug fit, you will have to place the car accurately in the bag in order to zip up around it.