We claim the ornamental design for a product stopper, as shown and described.
FIG. 1 is a front perspective view of a product stopper in accordance with the principles of the present disclosure, with additional broken lines showing a product distribution system to illustrate an example environment;
FIG. 2 is a front perspective view of the product stopper of FIG. 1;
FIG. 3 is a rear perspective view of the product stopper of FIG. 1;
FIG. 4 is a front view of the product stopper of FIG. 1;
FIG. 5 is a rear view of the product stopper of FIG. 1;
FIG. 6 is a top view of the product stopper of FIG. 1;
FIG. 7 is a bottom view of the product stopper of FIG. 1; and,
FIG. 8 is a left side view of the product stopper of FIG. 1, the opposing right side view being identical thereto.
Broken lines show elements that form no part of the claimed design. In this regard, broken lines showing the product distribution system in FIG. 1 illustrate an example environment that forms no part of the claimed design. While certain features of the product stopper, including the bounds thereof, are shown in solid lines, it should be appreciated that one or more of these certain features may be shown in broken lines forming no part of the claimed design. The shade lines in the drawing views show contour and not surface ornamentation of the product stopper.