Our Z3 Roof Cover works top up or down for added versatility. Shown here with the top down.
Here is a brief description of the attachment procedure.
On the back there are two "security tabs" that go into the drain well around the trunk. When the trunk lid is closed the cover cannot be removed. On the front there are VELCRO straps, one goes around each wiper arm and attached back on the cover. On the sides there are bendable felt covered pieces (bend in a "L" or "J" shape) on the end of an elastic strap. Each of these goes under the door. On the Z3 roof cover there are eight attachment points. This a very secure cover.
This cover has a four year warranty, it works top up or top down, has door dent protection, is a great UV shield, keeps water out, very easy to install/remove, and keeps prying eyes out of the car. It folds up to be about the size of a soccer ball and has its own storage bag. It is our best selling cover.