Parafilm's predictable oxygen transmission rates (OTR) helps to keep your experiments consistent. Gas permeability in 24 hours at 23 °C and 50% relative humidity: - O2 (oxygen): ≤ 350cm³/m² - N2 (nitrogen): ≤ 105cm³/m² - CO2 (carbon dioxide): ≤ 1100cm³/m² - Water vapor permeability in 24 hours at 37 °C and 90% relative humidity: 0.8 g/m² (Vapor pressure from volatile substances may lift PARAFILMM off the edge of the vessel.)