Male external catheter

1. 1The ornamental design for a male external catheter as shown and described.

FIG. 1 is a perspective view from above of a male external catheter showing my new design;
FIG. 2 is a perspective view from below;
FIG. 3 is a side view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a plan view thereof; and,
FIG. 6 is a bottom plan view thereof. 
The portions of the figures that are presented in broken lines merely illustrate the environment of the design and are not part of the claimed design.