Merit Brass XNL119-04 Brass Pipe Locknut 1/4 in Fnpt

Product Description

The MERIT BRASS XNL119-04 is a brass pipe locknut designed to secure fittings and bushings in threaded pipe assemblies. It provides a tight, vibration-resistant connection on FNPT (female national pipe taper) threaded pipe ends. Rated at 125 psi at Class 125, this locknut is suited for low- to medium-pressure plumbing and fluid distribution lines. The lead-free brass construction meets regulatory requirements for potable water applications. Plumbers and pipefitters install this part where a secure, leak-tight locknut is needed on 1/4 inch threaded pipe connections.

This locknut is used in residential and light commercial plumbing systems wherever a 1/4 inch FNPT threaded connection requires mechanical securing of a fitting, valve body, or tank fitting. Common install scenarios include water supply lines, compressed air distribution, and general fluid handling systems operating within the Class 125 pressure range. Its compact size makes it well suited for tight mechanical spaces where a standard wrench can still engage the hex profile.

Key Features

• Lead-free brass construction meets potable water compliance requirements
• 1/4 inch FNPT end connection for standard threaded pipe assemblies
• Class 125 pressure rating at 125 psi
• Brass material resists corrosion in water and air service applications
• Compact form factor suited for tight-clearance installations

Compatibility

Designed as an OEM-style replacement locknut for 1/4 inch FNPT threaded pipe fittings in Class 125 plumbing and fluid distribution systems.

Installation Notes

This fitting is installed by licensed plumbers or pipefitters in accordance with local plumbing codes and IPC guidelines. Shut off and depressurize the line before removing or installing any threaded fittings. Use an appropriate pipe wrench or open-end wrench to tighten the locknut — do not overtighten, as brass threads can be damaged by excessive torque. Apply thread sealant or PTFE tape to mating threads as required by the application and local code.