The ornamental design for a modular heatsink, as shown and described.
FIG. 1 is a perspective view of a modular heat sink of the present design;
FIG. 2 is a front view of the modular heat sink of FIG. 1, the opposite rear view being a mirror image thereof;
FIG. 3 is a top view of the modular heat sink of FIG. 1, the bottom, left and right side views of the modular heat sink of FIG. 1 being identical thereto;
FIG. 4 is a perspective view of a heat sink component of the modular heat sink of FIG. 1, shown separately for illustrating portions of the design not visible in FIGS. 1–3 of which four such heat sink components make up the modular heat sink of FIG. 1;
FIG. 5 is a front view of the heat sink component of FIG. 4, the opposite rear view being a mirror image thereof;
FIG. 6 is a left side view of the heat sink component of FIG. 4;
FIG. 7 is a right side view of the heat sink component of FIG. 4;
FIG. 8 top view of the heat sink component of FIG. 4; and,
FIG. 9 is a bottom view of the heat sink component of FIG. 4.