Fischer elektronik 5 3 extruded heatsink for pcb mounting fischer elektronik sk129 50 8 sts the fischer elektronik 5 3 extruded heatsink for pcb mounting has been designed to a high standard with solderable tinned connection pins for vertical installation for semiconductor clip mounting fischer elektronik sk129 50 8 sts sk129 50 8sts heat sink 5 3 c w