FIG. 1 is a perspective view of the new design for a handle hub;
FIG. 2 is a front view of the new design for a handle hub, the back, right side, and left side views being mirror images;
FIG. 3 is a top view of the new design for a handle hub; and,
FIG. 4 is a bottom view of the new design for a handle hub.
The broken lines in the Figures are for illustrative purposes only and form no part of the claimed design.