Woolmark describes non-medical mask constructions using either layered textiles or three-dimensional knitting. A Stoll machine can knit a shaped mask from wool-blend yarn as one piece, reducing subsequent assembly and allowing provision for an inserted filter.

One-Piece Knitting Shapes Non-Medical Wool Masks

Layered alternatives may combine densely woven water-resistant wool outside, a wool felt filter and superfine Merino against the skin. These components have different structural roles. The described KnitWarm mask does not meet surgical bacterial or particle filtration requirements, so its material construction should not be mistaken for medical certification.