FIG. 1 is a front elevational view of a hairbrush showing my new design;
FIG. 2 is a rear elevational view thereof;
FIG. 3 is a left side elevational view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a front perspective view thereof;
FIG. 7 is a rear perspective view thereof;
FIG. 8 is an enlarged view of portion 8 in FIG. 6; and,
FIG. 9 is an enlarged view of portion 9 in FIG. 7.
The broken lines shown in the drawings illustrate both the bounds of the portions of the claimed design that appear in the enlarged views and define the edges of the enlarged views. The broken lines form no part of the claimed design.