Abstract: A respirator (10) having an oral-nasal unit (12) with a peripheral seal that seals around the nose and mouth of a wearer's face and having an inlet aperture (40) connectable to a supply of breathable air, and an outlet aperture (42). The unit having a rigid insert (106) with an exterior profile adapted to seat against a correspondingly shaped interior surface of the unit (12); an outlet conduit (112) with a tube adapted to extend through the exhale aperture (40) of the unit (12); and a wing portion (110) with a through aperture (122) registering with the unit's inlet aperture (40). The outlet conduit (112) having a bayonet connector (130, 132) that enables the unit to interchangeably and detachably connect to, a connector formed as part of an exhale aperture of a full-face mask, or of a harness assembly (102). The bayonet connector forms an airtight seal between the two.

Abstract: A bayonet connector (112, 128) suitable for connecting a filter cartridge (72) or an air supply tube to a respirator (10, 14). The bayonet connector (112) has a tubular male part (112) and a female part. The male part has a tube (114) with two or more lugs (130, 132) formed on it, which engage with engaging ribs (136, 138) located on an interior sidewall of the female part (128), or vice versa. The lugs (130, 132) and their corresponding engaging ribs (136, 138) are located at different axial positions.