Used to control humidity and reduce evaporation of samples. They prevent spills and contamination. Cold seals are self-sticking with inert adhesive. Heat seals are available in a clear polyester or aluminum foil. Heat seals are for polypropylene microplates only and are applied with heat and pressure.- Seals, Clear Polyester Thin Cold Sealing Film with Adhesive Backing, 0.05mm Thick, 100/pk