Aavid thermalloy 6399b 3 3 c w bolt on heat sink for to 218 to 220 to 247 aavid thermalloy 6399b a high power extruded bolt on heat sink with large radial fins and solderable shoulder pins suitable for use with to 218 to 220 or to 247 type components aavid thermalloy 6399b heat sink for to218 to220 and to247 3 3 c w bolt on type