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 very baked by the sun and thus dry out and crack. The other problem comes from people that have the car painted without removing these and thus they are often painted on. Made for the larger Mk3 window this can be cut and shortened along the top horizontal as a substitute for the correct one discontinued over 30 years ago.