| 释义 |
An orinasal mask is a breathing mask that covers the mouth and the nose only. It may occur independently, as an oxygen mask, or on some anaesthetic apparatuses, or it may occur inside a fullface mask on a scuba set, a gas mask or an industrial breathing set to reduce the amount of dead space. It may be designed for its lower edge to seal on the front of the lower jaw or to go under the chin. {{underwater-diving-stub}} 3 : Industrial breathing sets|Underwater breathing apparatus|Functional masks |