These heavy-duty filter discs are designed for 1/2 gallon spawn jars with a 110 mm diameter opening. They allow for gas exchange while providing 99.97% efficiency filtration down to 0.3 microns. Autoclavable. They are 100% reusable and the best filter available for spawn production or canning jar cultivation.
To use this filter, simply fit it snugly under the jar lid, or place it on top of the jar lid and secure it with the jar band.