Light-tight Tarp Zip A peel and stick zipper that adheres to any plastic or poly sheeting. Wherever you want to make a door in your plastic sheeting, you stick this zipper on, unzip the zipper, cut through the tarp zip and the plastic at with one cut and then you have a fully closable door. The best part is that it is light tight unlike other brands. Competing brands allow light to bleed through the zipper which basically makes them useless in greenhouse situations. Length: 6 feet.