Glass rear windows greatly enhance rear visibility. They are not prone to scratching, cracking or yellowing due to exposure to the sun. 1964 - 1970 rear windows have a visible urethane folding seam. 1971 - 1973 are solid glass. 1964 - 1966 must use 67 - 70 convertible well liner. 1964 - 1970 folding seam carries an 18 month warranty against splitting or separation. Glass rear window and top are now packaged in 1 box to save on shipping cost.