It blocks the hot sun.  It fits perfectly.  But ... when it's not in use, it rolls up into a 6 inch by 36 inch tube.  It has a handy built-in strap to keep it rolled up.  If your trunk is empty, no problem.  If your trunk is full, this has to live in the back seat.  It is too stiff to fold flat.  So there's a trade-off that is obvious when you see the item, but not so much when you order it online.  I'd say that if you are going to use it every day, it's fine that it's big when off the window. If you only use it occasionally and never fill your trunk, it's still fine.  If you use it occasionally and often or always have a full trunk, then this might not be perfect, unless it's ok to keep it in the back seat. If you also get the ones for the side window and/or the back window, you need homes for those, too, when they are not blocking the sun.
It blocks the hot sun. It fits perfectly. But... when it's not in use, it rolls up into a 6 inch by 36 inch tube. It has a handy built-in strap to keep it rolled up. If your trunk is empty, no problem. If your trunk is full, this has to live in the back seat. It is too stiff to fold flat. So there's a trade-off that is obvious when you see the item, but not so much when you order it online. I'd say that if you are going to use it every day, it's fine that it's big when off the window. If you only use it occasionally and never fill your trunk, it's still fine. If you use it occasionally and often or always have a full trunk, then this might not be perfect, unless it's ok to keep it in the back seat. If you also get the ones for the side window and/or the back window, you need homes for those, too, when they are not blocking the sun.