B K Mueller 521-806HN Black Plain Plug 1-1/4 in

Product Description

The B K Mueller Inds Import 521-806HN is a black plain plug designed to cap and seal threaded pipe openings in plumbing and piping systems. At 1-1/4 inches, this plug fits standard NPT-threaded pipe ends and is used to close off unused ports, branch connections, and test points. The black iron finish is consistent with typical black steel pipe systems used in gas, steam, and water applications. Plumbers and pipefitters install this type of plug as part of routine service, new installation, and pressure-testing work.

This plug is suited for residential and light commercial piping applications where a threaded end must be sealed. Common scenarios include capping unused tee outlets on gas distribution lines, closing off test ports after pressure checks, and sealing branch connections during phased construction. The 1-1/4 inch size addresses a common pipe size found in main gas supply runs, larger drain lines, and commercial water distribution headers. This item is sold in a package quantity of 5.

Key Features

• 1-1/4 inch size fits standard NPT-threaded pipe openings
• Black iron finish compatible with black steel pipe systems
• Plain plug design provides a clean, low-profile seal on threaded ports
• Sold in a package of 5 units for jobsite and shop stock efficiency
• Suitable for gas, steam, and water piping applications

Compatibility

Designed as an OEM-style threaded plug for use with 1-1/4 inch NPT black iron or steel pipe fittings in standard plumbing and piping systems.

Installation Notes

Installation is performed by licensed plumbers or pipefitters following applicable code requirements such as the IPC and IFGC. Shut off gas or water supply and depressurize the line before installing or removing any threaded plug. Apply appropriate pipe thread sealant or PTFE tape to the male threads before seating the plug. Use a properly sized pipe wrench or socket to achieve a secure, leak-free connection without overtightening cast or malleable iron fittings.