The ornamental design for a refill for a digitalpen, as shown and described.
FIG. 1 is an environmental view of a refill for a digital pen according to an embodiment of our new design;
FIG. 2 is a top front perspective view thereof;
FIG. 3 is a bottom rear perspective view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a front view thereof;
FIG. 7 is a rear view thereof;
FIG. 8 is a top view thereof; and,
FIG. 9 is a bottom view thereof.
The broken lines in the drawings show portions of the refill for a digital pen which form no part of the claimed design. While the solid lines in the drawings form part of the claimed design, the solid lines also provide written description of prospective embodiments with aspects that are not claimed when one or more of the solid lines are amended to broken lines.