Many models of filtering half-masks feature a foldable 2-panel or 3-panel design that provides compactness and ease of use. Such a half-mask easily fits in a workwear pocket, takes up little space and does not cause discomfort during use.
Light half-masks typically have a 2-panel design. One of their main advantages is compactness.
More complex models feature a 3-panel design; many users call them the most comfortable, because a 3-panel half-mask follows facial movements and fits a variety of face shapes.