Heater

FIG. 1 is a front, top, and right side perspective view of a heater, showing my new design;

FIG. 2 is a perspective view of a heater shown in an environment of use.

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken lines shown in the drawings illustrate portions of the heater that form no part of the claimed design. The broken lines in FIG. 2 showing another heater illustrate environmental structure and form no part of the claimed design.