We take cryptocurrency — so the coins you hold can buy real hardware.Pay in crypto, spend it on real hardware. Free insured shipping worldwide over $399. Plain, unbranded boxes, sent from Germany.Free insured shipping over $399. Your rate is locked for 30 minutes once checkout opens.Rate locked 30 minutes. Every item sealed, serial-checked and covered by a 24-month warranty.Sealed, 24-month warranty.

Saved items Sign in
Black 3 inch coupling with female threads both ends

Legend Valve

Legend Valve 350-510 3" Black Coupling FNPT x FNPT

SKU CH-TGX8-VRTRY

A 3-inch black coupling with female NPT threads on both ends connects two pipes of the same size

  • 3-inch FNPT coupling connects pipes securely
  • Black steel construction resists corrosion in plumbing systems
  • Legend Valve brand delivers reliable fluid-handling components
  • Female threads on both ends simplify installation
  • Prop 65 notice flags chemical content for safety awareness

3" Black Coupling FNPT x FNPT

This 3-inch black coupling connects two female NPT threaded pipes in plumbing systems. It provides a straight, leak-resistant joint for water, gas or air lines. The fitting is manufactured by Legend Valve and supplied new.

Installers joining two FNPT ends

Suits plumbers and maintenance teams who need a simple 3-inch FNPT-to-FNPT connection in black steel. Not for users who require a reducing coupling, a different thread standard or a material other than black steel.

California Proposition 65 notice

This product contains a chemical known to the State of California to cause cancer and birth defects or other reproductive harm. The warning applies to the coupling as supplied and should be reviewed before installation.

Highlights

  • 3-inch FNPT coupling connects pipes securely
  • Black steel construction resists corrosion in plumbing systems
  • Legend Valve brand delivers reliable fluid-handling components
  • Female threads on both ends simplify installation
  • Prop 65 notice flags chemical content for safety awareness

Specifications

BrandLEGEND VALVE

Questions about this item

Will the 350-510 coupling thread onto my existing 3-inch black iron pipe?

Yes, both ends are 3-inch FNPT so they accept standard male NPT threads on black iron pipe.

How do I verify the joint is sealed after assembly?

Pressurise the line and brush soapy water on each thread; bubbles indicate a leak that needs more sealant or tightening.

Does the box include thread sealant or tape?

The coupling ships alone; you must supply PTFE tape or pipe dope separately.

Also in this aisle

People compared these

Same shelf, same checkout — eight coins and a 30-minute rate lock.