Breathe-Easier™ micro-permeable membranes allow gas exchange while keeping contents protected from airborne contaminants. Ideal for growing cells or concentrating samples. The membranes are made from white, non-woven rayon that transmits water vapor at a rate of 4.2 kg/m²/24 hours. The functional temperature range is -20°C to +80°C. 100/pack; sterile.