80% Polyester/20% Cotton When properly installed, any Thermaplus blackout product will block 100% of all incoming light and provide you with a 100% true blackout experience ideal for watching movies, playing video games and getting a restful night’s sleep. The layered properties create a hotel quality 100% true, total blackout environment while also providing absolute privacy, heating and cooling cost-cutting benefits, as well as sound dampening. Instantly turns any window curtain into a 100% total blackout one. The multi-purpose header can fit behind a Grommet top, pinch pleat, tab top, and even a tailored panel. To either attach or hang behind your curtain. The package includes one 45-inch wide curtain liner. Compatible with any curtain with a 40" to 54" in width. This 88-inch length curtain liner best fits a curtain up to an 84-inch length.