The ornamental design for a heatsink, as shown and described.
1., 3.-4. Heat sink
1.1 : Front
1.2 : Back
1.3 : Top
1.4 : Bottom
1.5 : Left
1.6 : Right
1.7 : Top perspective view
1.8 : Bottom perspective view
1.9 : Cross-sectional
3.1 : Front
3.2 : Back
3.3 : Top
3.4 : Bottom
3.5 : Left
3.6 : Right
3.7 : Top perspective view
3.8 : Bottom perspective view
3.9 : Cross-sectional
4.1 : Front
4.2 : Back
4.3 : Top
4.4 : Bottom
4.5 : Left
4.6 : Right
4.7 : Top perspective view
4.8 : Bottom perspective view
4.9 : Cross-sectional
The articles are heat sink for heat release and cooling of electric and electronic equipment, such as television integrated circuits and lighting apparatus; reproduction No. 1.9 is a cross-sectional view sectioned vertically at the center of the right view No. 1.6; reproduction No. 3.9 is a cross-sectional view sectioned vertically at the center of the right view No. 3.6; reproduction No. 4.9 is a cross-sectional view sectioned vertically at the center of the right view No. 4.6.