The ornamental design for a buckle for bag, as shown and described.
FIG. 1 is a front, top, and right perspective view of a buckle for bag, showing the claimed design;
FIG. 2 is a front view thereof;
FIG. 3 is a back 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;
FIG. 8 is a cross-sectional view taken along line 8-8 shown in FIG. 2;
FIG. 9 is a front, top, and left perspective view thereof;
FIG. 10 is a front, top and right perspective view thereof, showing a state in which a hook portion is unhooked; and,
FIG. 11 is a reference view showing the buckle for bag in use.
The long dash short dash broken lines and arrows shown in FIG. 2 are used to identify the cross-sectional view and form no part of the claimed design. The portions of the buckle for bag shown in broken lines in FIGS. 3 and 4 form no part of the claimed design. The evenly spaced broken lines shown in FIG. 11 depict environment and form no part of the claimed design.