P100 half-face<unk>  filter mask worn by a NYPD officer;alt Similar mask with generic flat disk filters.<unk> s, also called reusable air-purifying respirators, seal to the face with<unk>  material, which may be a natural or synthetic rubber. They are generally reusable. Full-face versions of<unk> s seal better and protect the eyes.<unk> s consist of a reusable mask that seals to the face, with exchangeable filters.<unk> s can be used with chemical cartridge filters that remove gases, mechanical filters that retain particulate matter, or both. As particulate filters, they are comparable (or, due to the quality and error-tolerance of the<unk>  seal, possibly superior) to filtering facepiece respirators such as N95 respirators and FFP masks.<unk>  air-purifying respirators are reusable because the facepiece is cleaned and reused, but the filters are discarded and replaced when they become unsuitable for further use. Some, but not all, filter materials are proprietary and manufacturer-specific, and supply-chain failures can make replacements hard to find. Although powered air-purifying respirators and air-supplying respirators may have<unk>  masks, they are not generally referred to as<unk> s.
Elastomeric respirator
Bubble oxygenator
Venturi mask
Negative pressure ventilator
N95 respirator
Laryngeal mask airway
Tracheotomy
Gas mask