The ornamental design for a handheld remote controlunit, as shown and described.
FIG. 1 is a perspective view of a handheld remote control unit showing my new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a bottom plan view thereof;
FIG. 4 is a right side elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a front elevational view thereof; and,
FIG. 7 is a rear elevational view thereof.
The broken lines in FIGS. 1, 2, and 4-7 indicate lines on the unit which form no part of the claimed design. The broken lines in FIG. 3 indicate surfaces which form no part of the claimed design.