Parafilm M

Parafilm M is a flexible, thermoplastic, waterproof self-sealing film that holds moisture loss to the minimum and offers secure sealing to the content of tubes, beakers, flasks, petri-dish and vials. It has excellent resistance to air, other gases, alcohol, common acids and moderately concentrated alkalis. At 21° C (70° F), it stretches 200% and returns partially to its original size at 82° C to 93° C (180° F to 200° F) and softens enough to make an adhesive bond between papers, cloths and leathers.