Millipore MilliWrap™ membrane sealing wrap film is the ideal replacement for metal caps, Parafilm*, cotton plugs and lids on all types of laboratory flasks, dishes, bottles and containers. These disposable membrane filtering sheets are composed of hydrophobic PTFE (polytetrafluoroethylene) and are treated with an antitoxic acrylic adhesive. Apply as a clean barrier that allows samples to vent while preventing contamination from condensation and airborne particles such as mold, spores and dust. MilliWrap™ membrane sealing wrap is ideal for cell culture, botanical studies, media preparation, nitrogen studies and parasitology. Also useful in laboratory experiments where the expansion of air due to boiling or a chemical reaction can cause the container to explode if not ventilated. Milliwrap™ has a 0.45µm pore size and is 0.2mm thick. Milliwrap™ is packaged in a dispensing roll allowing you to tear off only the perfect size sheet to seal your laboratory vessel. PTFE membranes are chemically resistant to most solvents.