The ornamental design for a handle for a masonjar, as shown and described.
FIG. 1 is a top perspective view of a handle for a mason jar showing the design;
FIG. 2 is a top perspective view of the handle of FIG. 1 shown in use;
FIG. 3 is a side elevation view thereof of FIG. 1;
FIG. 4 is an opposing side elevation view of FIG. 1;
FIG. 5 is a top elevation view of FIG. 1;
FIG. 6 is a bottom elevation view of FIG. 1;
FIG. 7 is a rear elevation view of FIG. 1; and,
FIG. 8 is a front elevation view of FIG. 1.
In the drawings, the broken lines depict environmental subject matter only that forms no part of the claim. The handle for a mason jar is shown with a symbolic break in its length. The appearance of any portion of the article between the break lines forms no part of the claimed design.