The ornamental design for a switchbox, as shown and described.
FIG. 1 is a left, front and top perspective view of a switch box, showing our new design;
FIG. 2 is a right, rear and bottom perspective view of the switch box of FIG. 1;
FIG. 3 is a left side view of the switch box of FIG. 1;
FIG. 4 is a front side view of the switch box of FIG. 1;
FIG. 5 is a right side view of the switch box of FIG. 1;
FIG. 6 is a rear side view of the switch box of FIG. 1;
FIG. 7 is a top side view of the switch box of FIG. 1; and,
FIG. 8 is a bottom side view of the switch box of FIG. 1.
The broken lines immediately adjacent the shaded areas represent the bounds of the claimed design while all other broken lines are for the purpose of illustrating environment only and form no part of the claimed design.