Made by Matilda's Own - this is what they have ti say about their product:
"Using the knowledge gained by making mask filters for the CSIRO in recent trials, we have created this highly efficient face mask filter. 100% Made in Australia from Hollow Conjugated Polyester for moisture absorption and extremely effective particle filtration".
Each pack contains 4 x A4 sheets, measuring 210mm x 297mm for use with your own cotton outer.
Makes up to 24 refills. Refills are washable but we recommend replacing them after each use.