This mask has been thought out and produced by a retired Critical Care Nurse. The mask is designed with a stiff wire to contour over the nose for creating a seal over the bridge of the nose and upper face. (Note: with clean hands shape the wire with thumb and fingers to fit over nose). A 10 cm. opening has been provided at the bottom of the mask for insertion of additional filter material ( N95 particulate or hepa filter material) should the individual desire more protection. It is washable and reusable.