a belt - line weather sealing strip for sealing the opening between a vehicle window housing and a slidable window pane includes an elongate , relatively rigid , thermoplastic base having at least one integrally attached thermoplastic resilient fastening means which extends downwardly and has a longitudinal slot which is capable of engaging an aperture edge portion of the housing forming the belt - line portion of the window opening . the sealing strip also includes a relatively flexible , elastomeric sealing element joined to the thermoplastic base . the fastening means is inserted downwardly through a vehicle window housing aperture and then moved horizontally to effect a secure engagement of the sealing strip with the housing .