We claim the ornamental design for a mixer tap, as shown and described.
FIG. 1 is an isometric front view showing the new design.
FIG. 2 is an isometric rear view of the new design.
FIG. 3 is a front view of the new design.
FIG. 4 is a rear view of the new design.
FIG. 5 is a right side view of the new design.
FIG. 6 is a left side view of the new design.
FIG. 7 is a top view of the new design; and,
FIG. 8 is a bottom view of the new design.
The broken line(s) shown in the drawings are for illustrative purposes only and form no part of the claimed design.
The shading lines shown in the drawings represent the approximate three-dimensional contour of the design, and are not intended to indicate surface decoration.