The ornamental design for the hair brush, as shown and described.
FIG. 1 is a perspective view of the hair brush in accordance with the principles of the present disclosure;
FIG. 2 is a top plan view of the hair brush;
FIG. 3 is a side elevation view of the hair brush;
FIG. 4 is a front axial view of the hair brush;
FIG. 5 is a bottom plan view of the hair brush; and,
FIG. 6 is a rear axial view of the hair brush.
The broken line immediately adjacent the shaded area near the distal end of the handle represents the bounds of the claim and forms no part thereof while all of other broken lines on the handle and the broken lines showing the bristles illustrate portions of the hair brush that form no part of the claimed design.