The ornamental design for a hairbrush handle, as shown and described.
FIG. 1 is a side elevational view of a hairbrush handle showing my new
design, the oppoiste side being a mirror image;
FIG. 2 is a top plan view thereof; and,
FIG. 3 is a bottom plan view thereof.
The undisclosed ends of the handle are unornamented. The broken line
showing of a brush head is for illustrative purposes only and forms no
part of the claimed design.