These left and right grilles are only applied on the VW Beetle model year 71 and serve to conduct air over the rear window to de-mist it.Later they are replaced by 6 separate grilles, 3 on each side (BBT 0780-1 & 0780-2) Originally these were made of thin plastic, which becomes brittle through the years and therefore simply crumble when you want to dismantle them or they are simply already gone. These new grilles are made of 2.5mm thick polyester with the correct structure and white colour which makes them a lot more durable than the original ones.