We claim the ornamental design for a unidirectional valve for face mask, as shown and described.
FIG. 1 is a perspective view of a unidirectional valve for face mask in accordance with the present design;
FIG. 2 is a top view thereof;
FIG. 3 is a bottom view thereof; and,
FIG. 4 is a side view thereof.
The dash-dot-dash broken lines in the figures represent the boundaries of the claim design and form no part thereof. The dash-dash broken lines in the figures are for the purpose of illustrating portions of the unidirectional valve for face mask and form no part of the claimed design.
CORRECTIVE ASSIGNMENT TO CORRECT THE TYPOGRAPHICAL ERROR IN THE RECEIVING PARTY DATA PREVIOUSLY RECORDED AT REEL: 052579 FRAME: 0120 ASSIGNOR S HEREBY CONFIRMS THE ASSIGNMENT