This is the seal that goes on the front edge of the rear windows and meets up with the door glass when you shut the doors. This is the rubber seal only, the chrome piece that it fits into is not included but is available separate, it is called the quarter window seal retainer.
The quarter window seals fit 1971-1976 Chevrolet Impala & Caprice convertible or 2 door hardtop and are sold as a pair.
