FIG. 1 is a top perspective view of a mask filter in an open configuration;
FIG. 2 is a bottom perspective view of the mask filter of FIG. 1;
FIG. 3 is a top view of the mask filter of FIG. 1;
FIG. 4 is a right side view of the mask filter of FIG. 1;
FIG. 5 is a bottom view of the mask filter of FIG. 1;
FIG. 6 is a left side view of the mask filter of FIG. 1;
FIG. 7 is a front view of the mask filter of FIG. 1;
FIG. 8 is a back view of the mask filter of FIG. 1;
FIG. 9 is a top perspective view of the mask filter in a closed configuration;
FIG. 10 is a bottom perspective view of the mask filter of FIG. 9;
FIG. 11 is a top view of the mask filter of FIG. 9;
FIG. 12 is a right side view of the mask filter of FIG. 9;
FIG. 13 is a bottom view of the mask filter of FIG. 9;
FIG. 14 is a left side view of the mask filter of FIG. 9;
FIG. 15 is a front view of the mask filter of FIG. 9; and,
FIG. 16 is a back view of the mask filter of FIG. 9.
The broken lines in the drawings depict portions of the mask filter that form no part of the claimed design.