Brass 4 1/2" NH to 4" NPT Double Male (Hex) Pick One Side_6 inch you need this plug

you need this plug

7 1/2 threads per inch and male 1 1/2 inch NH

If possible it is best to measure the MALE fitting

This is the same water-handling accessories spanner wrench found in the Defense Logistics Agency (DLA) Wildland Fire Equipment catalog or Fedmall

US Coast Guard approval number 162

Brass 4 1/2" NH to 4" NPT Double Male (Hex) Pick One Side_6 inch you need this plugMale to male adapters are used to bridge male to female hoses, pipes or valve fittings. Brass is commonly chosen for corrosion resistance, and is popular with chemical or salt water applications. Compatible part number DMH4045F WARNING: This product contains a chemical known to the State of California to cause birth defects or other reproductive harm. Do not use in connection with drinking water. Wash hands after handling. Brass Male to Male Adapter