Plug

FIG. 1 is a perspective view showing our new design; FIG. 2 is a top plan view thereof; FIG. 3 is a bottom plan view thereof; FIG. 4 is a first side elevation view thereof; FIG. 5 is a second side elevation view thereof; FIG. 6 is a rear elevation view thereof; and, FIG. 7 is a front elevation view thereof. The broken lines in the drawings depict portions of the plug that form no part of the claimed design.