I claim the ornamental design for a hair iron, as shown and described.
FIG. 1 is a left side view of a hair iron showing the new design;
FIG. 2 is a bottom plan view thereof;
FIG. 3 is a front end side view thereof;
FIG. 4 is a rear end view of a hair iron;
FIG. 5 is a right side view of a hair iron;
FIG. 6 is a top plan view of a hair iron; and,
FIG. 7 is a view of a portion of the front end thereof detailing alternative end features.
The end portion of the hair iron is shown separately in FIG. 7 for convenience of illustration.
The broken lines connecting the outer solid lines of the hair iron represent the bounds of the claim. The remaining broken lines illustrate portions of the article. None of the broken lines forms part of the claimed design.