noun
facepiece; face mask part
Technical term for the part of a respirator, gas mask, or similar device that covers the face. Not a general word for mask.
この防毒マスクの面体はシリコン製です。
The facepiece of this gas mask is made of silicone.
面体が顔にしっかりフィットしているか確認してください。
Please check that the facepiece fits snugly against your face.