The ornamental design for a back design for irongolf club heads, as shown and described.
FIG. 1 illustrates an angled, perspective view of a new design of an iron golf club head;
FIG. 2 illustrates a rear view of the design shown in FIG. 1;
FIG. 3 illustrates an angled rear perspective view of the design shown in FIG. 1;
FIG. 4 illustrates an angled bottom-perspective view of the design shown in FIG. 1;
FIG. 5 illustrates an angled perspective view of the design shown in FIG. 1 taken from the heel;
FIG. 6 illustrates an angled perspective view of the design shown in FIG. 1 taken from the toe;
FIG. 7 illustrates a side view of the design shown in FIG. 1 taken from the top perimeter edge of the club;
FIG. 8 illustrates an angular perspective view of the design shown in FIG. 1 taken from the bottom perimeter edge of the club; and,
FIG. 9 illustrates a rear view of the club of the design shown in FIG. 1 taken from the heel.
The broken, dashed lines shown in the various figures depicting embodiments of the invention are included for the purpose of illustrating environment and do not form any part of the claimed design.