I claim the ornamental design for a product merchandiser, as shown and described.
FIG. 1 is a perspective view of a product merchandiser, showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is a left side elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines shown in the drawings represent unclaimed environment only and form no part of the claimed design. Dash-Dot Broken lines show boundaries between claim and unclaimed portion of the design. The break lines that separate the parts of the product merchandiser and the portion within the break lines represent indeterminate length and form no part of the claimed design.