We claim, the ornamental design for a metal detector, as shown and described.
FIG. 1 is a perspective view drawing of a metal detector according to an embodiment of the design.
FIG. 2 is a perspective view drawing of a metal detector according to an embodiment of the design.
FIG. 3 is a perspective view drawing of a metal detector according to an embodiment of the design.
FIG. 4 is a perspective view drawing of a metal detector according to an embodiment of the design; and,
FIG. 5 is a perspective view drawing of a metal detector according to an embodiment of the design.
The several drawing figures illustrate a search coil, in broken line, attached to the claimed metal detector. The purpose of the broken line search coil is to illustrate an application of the metal detector, and the broken line search coil portion of the drawing figures do not form a part of the presently claimed metal detector.