3a 1st end thread class 12 1st end thread quantity per inch machined groove in flared ends to accommodate seal rings per KC103 passivate outside surface treated un 1st end thread series
3a 2nd end thread class 16 1st end thread quantity per inch drill one .03125 in. dia hole on bulkhead side of nipple anodize inside surface treated un 1st end thread series
2b 2nd end thread class 18 2nd end thread quantity per inch machined groove in flared ends to accommodate seal rings per KC103 passivate outside surface treated unf 1st end thread series