ZipWall heavy-duty zippers are the quickest way to create an entry in a plastic dust barrier wherever you need it. Two ZipWall zippers create a hands-free entry – simply roll up the flap and hold the door open using two flap hooks. This hands-free door can be as wide as needed to get equipment and supplies in and out of the worksite. Patented ZipperKnife sheeting cutter PREVENTS JAMS. Specially designed to double-cut the plastic, the ZipperKnife leaves a clean cut that keeps plastic away from zipper teeth. Note: A single zipper may be used to create a fly-door. Contents: Two zippers, two flap hooks, and one ZipperKnife sheeting cutter.