3-ply single use filters designed to fit into our Reusable Face Masks designs (#100643, #100684) Intended for single use, slide one inside your reusable face mask filter pocket before each use. Made from the same materials as our single use face mask, #250. Outer layer: PP non-woven. Middle/Filter layer: melt-blown PP non-woven. Inside layer: PP- non-woven. BFE greater or equal to 95%. Filters are individually sealed and packaged in a bag in increments of 10.