Two parts which are sometimes easily confused are replacement boot covers and replacement tonneau covers. Both of these parts are used when the convertible top is folded down (i.e. open) but they have very different functions.

A boot cover (also sometimes called a “parade cover” or “top cover”) covers the top opening. It gives the car a tidier appearance, and can help prevent “crud” and road grime from working its way into the crevices, particularly if the top is down for an extended drive.

On convertible cars, the tonneau cover is deployed to cover up the back and/or passenger seat. (Not to be confused with the term “tonneau cover” for pickup trucks, which is the sheet that can be used to cover the truck bed. Or with the roll-out screen on some hatchbacks, which can be used to shield the contents of the trunk from view.)

A tonneau cover not only protects your upholstery from damage, it can also reduce the annoying buffeting effect from wind turbulence inside the cabin. And it helps retain heat, which can make driving in cold weather a more pleasant experience. Finally, tonneau covers can reduce drag, thus improving gas mileage.