We claim the ornamental design for an inverter, as shown and described.
FIG. 1 is a front elevational view of the inverter of the invention;
FIG. 2 is a left elevational view of the inverter of the invention;
FIG. 3 is a right elevational view of the inverter of the invention;
FIG. 4 is a top plan view of the inverter of the invention;
FIG. 5 is a bottom plan view of the inverter of the invention;
FIG. 6 is a front isometric view of the inverter of the invention;
FIG. 7 is a front isometric view of the inverter of the invention showing an alternative position of the folding handles on the left and right sides of the inverter; and,
FIG. 8 is a front elevational view of the inverter of the invention showing the alternative position of the folding handles on the left and right sides of the inverter.