The ornamental design for a reflectivestrip, as shown and described.
FIG. 1 is a front view of the reflective strip;
FIG. 2 is a top view of the reflective strip;
FIG. 3 is a left side view of the reflective strip;
FIG. 4 is a right side view of the reflective strip;
FIG. 5 is a bottom view of the reflective strip;
FIG. 6 is a back view of the reflective strip; and,
FIG. 7 is a perspective view of the reflective strip, shown in a preferred environment in which the reflective strip is folded in half and clipped to a pocket.
The broken lines depict portions of the reflective strip that form no part of the claimed design. The broken lines shown in FIG. 7 depicting a pocket show a preferred environment and form no part of the claimed design.