Techni Ice 4ply White Reusable Ice Packs 4 ply Techni-Ice stays frozen longer than ever before! Techni Ice reusable dry ice packs / gel packs start as a flat sheet and absorbs water through a special perforation technology in the surface of the product. Can be used hot, cold or frozen Use for coolers, small fridges, or groceries. Can reduce the temperature in your freezer within 1 week.