Merit Brass X119-06 Brass Pipe Locknut 3/8 in Fnpt

Product Description

The MERIT BRASS X119-06 is a brass pipe locknut designed for threaded piping assemblies in plumbing, HVAC, and general mechanical systems. Sized at 3/8 inch with female NPT (FNPT) end connections, this locknut threads onto standard NPT fittings and pipe to secure and lock components in place against vibration, movement, or pressure. Rated at 125 psi, it is suited for low-to-medium pressure applications. Weighing approximately 0.04 pounds, the X119-06 is a compact, lightweight hardware item typically installed by licensed plumbers and pipefitters during rough-in or trim-out phases of a project.

This locknut is used in residential and light commercial piping systems where a threaded NPT connection must be mechanically locked. Common applications include securing fittings at valve packing glands, compression assemblies, and supply line connections. The FNPT threading allows direct engagement with standard male NPT pipe threads without additional adapters. It is sold in packages of 1 unit with a minimum order quantity of 6 units.

Key Features

• 3/8 inch FNPT threaded connection for standard NPT pipe and fittings
• Class 125 pressure rating at 125 psi for low-to-medium pressure service
• Brass construction provides corrosion resistance in water and fluid piping systems
• Lightweight at 0.04 pounds for easy handling and installation in tight spaces
• Threaded locknut design mechanically secures fittings against loosening

Compatibility

Designed as an OEM-style replacement or standard hardware fit for residential and commercial threaded NPT piping assemblies using 3/8 inch brass fittings rated at Class 125.

Installation Notes

Installation is typically performed by a licensed plumber or pipefitter in accordance with applicable IPC or local plumbing codes. Shut off the water supply and depressurize the line before installing or replacing any pipe locknut. Use appropriate pipe wrenches or open-end wrenches sized for the fitting — do not overtighten, as brass threads can be damaged by excessive torque. Inspect mating NPT threads for damage or debris before threading the locknut into place.