US D335337 S
FIG. 1 is a front perspective view of the heat exchanger for fuel fired furnaces;
FIG. 2 is a right side elevational view thereof, which is a mirror image of its left side elevational view;
FIG. 3 is a rear end elevational view thereof;
FIG. 4 is a front end elevational view thereof;
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a bottom plan view thereof.