The ornamental design for a hairretainingdevice, as shown and described.
FIG. 1 is a top view incorporating our new design; the bottom, front and
back views being mirror images of the top view;
FIG. 2 is a left side view; the right side view being a mirror image of the
left side view; and,
FIG. 3 is a perspective view of the device described in FIG. 1 shown
wrapped about human hair. The broken line showing of the human hair in
FIG. 3 is for illustrative purposes only and forms no part of the claimed
design.