Við vitum að það verður alltaf nefbrúarvír á grímunni, sem er notaður til að festa grímuna á nefbrúnni, en sumar neflínur eru ekki málmur heldur einnig plast.
Ef almennan einnota gríman er ekki meðnefbrúarvír, it cannot fit the mask well on the face. The top and sides of the mask will leak out. Wearing it while keeping a distance from the crowd can also play a protective role. However, in close contact, the protective effect of a mask without a nefbrúarvír will be greatly reduced, which greatly increases the risk of infection. As a medical surgical mask, if there is no nefbrúarvír, it is unqualified.