This high quality 1/8" thick Poly-carbonate flat window is the same size as the stock 911 window and is mar resistant with an anti-fog coating. It is designed to fit in the GT Racing Flush Frame on all 911, 964 and 993 models (GT Racing Part #51). This is a lower cost alternative for Race car folks who don't need a formed window. Approx weight 6 lbs (orig. glass 21 lbs).