Abstract: A molding strip is provided for sealing a gap between a slidable window pane and an adjacent frame structure. The molding strip is substantially S-shaped and comprises an inverted U-shaped flange seat which shares a common wall with a U-shaped glass-run channel. The flange seat is comprised of a first elastomer while the glass-run channel is comprised of a second higher durometer elastomer. The higher durometer elastomer extends at least 25 percent of the height of the common wall so that the glass-run channel is held rigidly in position against the flange as well as against the window and the adjacent sheet metal mounting surface. The glass-run channel further includes interior and exterior sealing lips which form a sealing contact with the window pane. The contacting surface of the sealing lips and the window channel base have a low friction surface.