The user can cut 1 Mask into a few squares  60mm x 60mm  or 2 3/8" by 2 3/8" to fit in the filter area. Then use the filter clamp to clamp it in place.  The filter square can be disposed of and the mask can be sanitized .  See www.makethemasks.com website   watch the  Making filters from standard mask   gasket assembl   nose cushion