Ideal for gas-generating media and autoclaving processes. In the centre, there is a sealed-in PTFE membrane, which allows for a quick and sterile pressure compensation. The membrane is gas-permeable, for both low pressure and excess pressure, and liquid-tight at the same time. The pressure compensation takes place in both directions. These characteristics also simplify autoclaving processes (up to +140°C), as the membrane cap can be screwed tightly and fixed onto the DURAN® bottle. The risk of contamination is greatly reduced. Ingress of liquids or solids is prevented and the bottle contents remain sterile.