The silicone sponge closure is manufactured with a sealed in .2 micron silicone sponge filter

Flange fits snugly over the necks of vessels permitting the exchange of gases, while reducing evaporation and preventing the passing of aerosols. Ideal for use with aerobic cultures. Reusable, autoclavable and will withstand dry heat sterilization up to 180°. Closure will withstand both dry heat sterilization and repeated autoclaving.