Used on aircraft, b-2 bomber (atb), support equipment (se), b-2 bomber; aircraft, f/a-18 hornet. 3a 2nd end thread class 18 2nd end thread quantity per inch weapon system essential unjs 1st end thread series
3a 2nd end thread class 12 1st end thread quantity per inch 2nd end bulkhead thd 1.062-12 in., cl 3a, unj passivate surface treated unj 1st end thread series