HDAZ2 The ZipWall® Heavy-Duty Zipper works as well for permanent access through plastic barriers as it does for temporary access. Each box of two sippers come with the exclusive ZipWall® Zipper Knife™. It cuts a swath of plastic away from the zipper teeth preventing jams. Works in temperatures below freezing. This adhesive zipper features 2-sided pulls, a very smooth glide action and easy press-on application.