Merit Brass XNL119-08 Brass Pipe Locknut 1/2 Inch Fnpt

Product Description

The MERIT BRASS XNL119-08 is a lead-free brass pipe locknut designed to secure threaded fittings in plumbing and piping assemblies. Built to Class 125 standards with a 125 psi pressure rating, this locknut uses a female NPT (FNPT) threaded connection and fits a 1/2 inch pipe size. It is manufactured from brass, which offers reliable corrosion resistance in water supply and general plumbing service. Licensed plumbers and pipefitters install this hardware type during fixture rough-in, valve mounting, and panel penetration work where a threaded locknut is required to hold a fitting or bushing tight against a surface.

This locknut is suited for residential and light commercial plumbing applications. Typical use cases include securing threaded fittings through panels, enclosures, or fixture bodies where a locking nut is needed to maintain connection integrity. The FNPT thread pattern is standard across North American pipe fittings, making this part compatible with common threaded brass, steel, and plastic fittings in water supply and distribution systems. Its lead-free construction meets requirements for potable water service where lead-free materials are mandated by code.

Key Features

• Lead-free brass construction suitable for potable water applications
• FNPT threaded connection compatible with standard NPT fittings
• Class 125 rating at 125 psi for general plumbing service
• 1/2 inch fitting size covers a common pipe dimension in residential and commercial work
• Compact, single-piece hardware — no additional components required

Compatibility

Designed as an OEM-style replacement or new-installation locknut for 1/2 inch FNPT threaded connections in Class 125 plumbing systems.

Installation Notes

Installation is performed by a licensed plumber or qualified pipefitter. Shut off the water supply and relieve system pressure before disassembling any threaded connection. Use an appropriately sized wrench to tighten the locknut to snug contact against the mating surface — do not overtighten brass fittings, as this can crack the material. Verify that all connections meet local plumbing code requirements, including applicable IPC or state-adopted code provisions for lead-free materials in potable water lines.