Hairbrush

FIG. 1 is a front perspective view of a hairbrush illustrating our ornamental design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a right-side elevation view thereof; and,

FIG. 8 is a left-side elevation view thereof.

The broken lines in the figures illustrate portions of the hairbrush which form no part of the claimed design.