Bad seals near the door windows make that humidity can penetrate in the empty space in the door. The parts within the door can get damaged through infiltrating moisture. The window sashes with Karmann Ghia are a nice example for it. In the past it was exceptional to find good second-hand window sashes, because most of the time they were severely damaged by rust. BBT has now a good reproduction window sash available each from stock. The window sashes fit on both sides.