We claim the ornamental design for an external defibrillator, as shown and described.
FIG. 1 is a perspective view of an external defibrillator, showing the new design with the device inserted into the base station;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a right side elevational view thereof.
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a partially exploded, front elevational view thereof showing how the device can be separated from the base station.
The broken lines immediately adjacent the shaded areas represent the bounds of the claim, while all other broken lines are directed to environment and are for illustrative purposes only; the broken lines form no part of the claimed design.