The ornamental design for a shower head, as shown and described.
FIG. 1 is a bottom plan view of a shower head, showing my new design;
FIG. 2 is a left side elevational view thereof, the right side, front and rear views being identical;
FIG. 3 is a top plan view thereof;
FIG. 4 is a perspective view thereof, from the bottom, left side and front; and,
FIG. 5 is a perspective view thereof, from the top, right side and front.
The characteristic feature of the design resides in its extremely reduced thickness, compared to the thickness of shower heads available in the prior art.