I claim the ornamental design for an urinal insert, as shown and described.
FIG. 1 is a perspective view of an urinal insert, showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left-side elevational view thereof, the right-side elevational view being a mirror image thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a bottom plan view thereof; and,
FIG. 7 is a cross-sectional view thereof, taken generally along lines 7-7 of FIG. 3.
The broken lines showing adjacent frangible inserts in FIGS. 1 and 2 and a urinal in FIG. 1 depict environmental matter and form no part of the claimed design.