Fischer elektronik aluminium heat sink mount to 220 fischer elektronik sk 75 25 sa the fischer elektronik aluminium heat sink mount 125cw to 220 is manufactured from alloy with a plate thickness of 4mm and a black anodised finish that increases radiative heat loss the heatsink is suitable for use with semiconductor packages of the to 220 type or similar fischer elektronik sk 75 25 sa heat sink for pcb mount 125cw to220