3a 2nd end thread class 12 1st end thread quantity per inch KC144C28-24; machined groove in flared ends to accommodate seal rings per KC103 passivate surface treated un 1st end thread series
3a 2nd end thread class 12 1st end thread quantity per inch KC144C16-4; machined groove in flared ends to accommodate seal rings per KC103 passivate surface treated un 1st end thread series
3a all ends thread class ion vapor deposition (ivd) w/ thickness of 0.0005; 18 thds per in. first end, 20 thds per in. second end chromate surface treated unjf all ends thread series