4N-N NPT Hex Socket Plug Thread Part No L Dash NPT mm -02 1/8-27 4N-N-02 8 -04 1/4-18 4N-N-04 12 -06 3/8-18 4N-N-06 12 -08 1/2-14 4N-N-08 15 -12 3/4-14 4N-N-12 16 -16 1-11.5 4N-N-16 20