The ornamental design for an earphone, as shown and described.
FIG. 1 is a perspective view of the front, top and left side of an earphone according to a first embodiment showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is a perspective view of the earphone shown in an environment of use.
The broken lines are included for the purpose of illustrating portions of the earphone and form no part of the claimed design. The broken line showing of a second earphone, cord, and controllers in FIG. 8 depicts environment and forms no part of the claimed design.