Non-Rebreather Mask

**Semantic type:** Manufactured Object

**Definition:** A facemask with a reservoir bag designed to deliver oxygen at a higher concentration than a low-flow nasal cannula or standard mask. It has a one-way valve between the mask and the reservoir so that oxygen flows only from the reservoir bag to the mask. A second one-way valve lets exhaled air flow out to the atmosphere while preventing atmospheric air entering back in.

**Synonyms:** - NRB - Non-Rebreather - Non-Rebreather Facemask