The ornamental design for buckle (Bea), as shown and described.
FIG. 1 is a front perspective view of a buckle showing my new design;
FIG. 2 is a top view of the belt shown in FIG. 1;
FIG. 3 is a bottom view of the belt shown in FIG. 1;
FIG. 4 is a left side view of the belt shown in FIG. 1;
FIG. 5 is a right side view of the belt shown in FIG. 1;
FIG. 6 is a front view of the buckle shown in FIG. 1;
FIG. 7 is a rear view of the buckle shown in FIG. 1; and,
FIG. 8 is a perspective view of the buckle shown in FIG. 1, shown in a buckled position, and in the environment of a belt.
The broken line showing of the buckle tongue, buckle hole, and portions of the belt in relevant drawings shows unclaimed subject matter for the design in those drawings.