The ornamental design for a shower head, as shown and described.
FIG. 1 is a perspective view of a shower head according to the present invention.
FIG. 2 is a front view of the shower head of FIG. 1.
FIG. 3 is a cross-sectional view of the shower head of FIG. 2; and,
FIG. 4 is a cross-sectional view of the shower head of FIG. 2.
The dashed lines illustrate environment that does not form a part of the present invention, and no claim is made to the material illustrated with dashed lines.