As to the question of rules regarding when and where peaceful protests may be held, that's highly dependent on the specific location of the protest.
The venturi mask, also known as an air-entrainment mask (and sometimes by the brand name VentimaskÂ®), is a medical device to deliver a known oxygen concentration to patients on controlled oxygen therapy.
Full face CPAP masks seal around your nose and mouth in the shape of a triangle and are held in place by four point headgear. These masks are used by people who breathe through their mouth during sleep and do not wish to use, or have not had success with, a nasal mask and chinstrap.