TO-3 POWER TRANSISTOR SOCKET. GOLD PLATED CONTACTS, 2 SOLDER LUGS. 0.04~ DIA PINS AT 0.43~ SPACING. (DIALLYL PHTHALATE INSULATOR) TO-3 Power TRANSISTOR SOCKET W/ GOLD P LATED CONTACTS AND DIALLYL PHTHALATE INSULATOR. (REV 10/91, JFK).