Plastic zip doors can be used to create temporary openings in structures contained with heat-shrink film.Cat.No.42727 is a self-adhesive white straight door measuring 170 x 30 cm.ONCE THE STRUCTURE HAS BEEN HEAT-SHRUNK:.1/ Position the door in the desired place.2/ Tape the door using tape Cat.No.42725.3/ Open the zip.4 /Make an opening using the Express Shrink Wrapping safety cutter Cat.No.42722.CAUTION:DO NOT HEAT.