Not every Mini has hinged rear quarter windows (rear side windows). This is the seal for the ones that don't open. The original rubber is prone to being baked by the sun, and they dry out and crack. The other problem comes from having the car painted without removing the window seals, and so they are often covered with paint. Made for the larger Mk3 window, this can be cut and shortened along the top horizontal for earlier models, since the correct one was discontinued 30 years ago.