A half face respirator masks covers the mouth and nose of the wearer, protecting the wearer from inhaling hazardous particles, gases and vapour that are airborne. The masks are tightly sealed around the mouth and nose. Similarly, to full face respirator masks, the body of the mask is reusable, and the filters require replacing when recommended. A half-mask might be a more cost-effective option if extra protection isn't needed or might be more suitable for combination with specialised headgear.