Part Number: 390000-PC234 (Special square head)Part Number: 390000PC234GAMMASP (Special square head)Part Number: 5305-00-468-0007 (Special square head)Part Number: 5305-468-0007 (Special square head)Part Number: 5306-00-427-0367 (Special square head)Part Number: 5306-427-0367 (Special square head)Part Number: 533825-PC234 (Special square head)Part Number: 58-11X1-78SPLSET (Special square head)Part Number: 674774 (Special square head)Part Number: 674774FRUEHAUF (Special square head)