External Square Plugs | McMaster-Carr

Filter by

System of Measurement

Pipe Size

Drive Style

Material

Thread Type

DFARS Compliance

Shape

For Use With

Fitting Type

Connects To

Gender

Fitting Connection

Length

RoHS Compliance

Body Shape

Maximum Pressure @ Temperature

Plug Construction

Pipe Material

Pipe Schedule

Pressure Class

Flange Material

REACH Compliance

Specifications Met

Forward

How can we improve?

322 Products

How to Identify and Measure Fittings

Pipe size is an industry designation, not the actual size. View information about how to measure threaded and unthreaded pipe and pipe fittings.

Compact Extreme-Pressure
Steel Threaded Pipe Fittings

These fittings are strong enough to handle extreme pressures, yet small enough to fit into cramped spaces.

Low-Pressure Iron and Steel Threaded Pipe Fittings

Use these fittings for low-pressure applications in noncorrosive environments.

Low-Pressure Iron and Steel
Threaded Pipe Fittings with Sealant

To prevent leaks in low-pressure lines, the male threads on these fittings have an acrylic sealant already applied for extra protection.

FM-Approved Low-Pressure
Cast Iron Threaded Pipe Fittings

Suitable for use in fire-protection applications, these pipe fittings are made of cast iron, so they are brittle and can be quickly opened with the strike of a sledge hammer.

Low-Pressure Galvanized Iron
and Steel Threaded Pipe Fittings

The galvanized finish on these fittings provides fair corrosion resistance. Fittings are for use in low-pressure applications.

Low-Pressure Galvanized Iron and Steel
Threaded Pipe Fittings with Sealant

The male threads on these fittings have a sealant applied for extra leak protection.

High-Pressure Iron and Steel Threaded Pipe Fittings

These fittings can stand up to high-pressure applications. Use them in noncorrosive environments.

Medium-Pressure Iron and
Steel Threaded Pipe Fittings

For use in noncorrosive environments, these fittings have better strength than our low-pressure iron and steel pipe fittings.

Low-Pressure Stainless Steel Threaded Pipe Fittings

Use these corrosion-resistant fittings in a low-pressure pipe line.

Premium Low-Pressure Stainless Steel
Threaded Pipe Fittings with Certification

Unlike other stainless steel fittings, these are made in the U.S.A. for superior quality. As another marker of quality, they come with a certificate with a traceable lot number and test report that guarantees material composition.

Low-Pressure Stainless Steel
Threaded Pipe Fittings with Sealant

The male threads on these fittings have a sealant applied for extra leak protection.

High-Pressure Stainless
Steel Threaded Pipe Fittings

Use these heavy duty, corrosion-resistant fittings in high-pressure flow applications.

High-Pressure Brass Threaded Pipe Fittings

These brass fittings have the strength to handle high-pressure applications.

High-Pressure Brass Threaded
Pipe Fittings with Sealant

Not only do these brass fittings have the strength to handle high-pressure applications, the male threads have a sealant applied for extra protection against leaks.

Low-Pressure Brass and
Bronze Threaded Pipe Fittings

Use these fittings in low-pressure flow applications. They have good corrosion resistance.

Low-Pressure Brass Threaded
Pipe Fittings with Sealant

The male threads on these brass fittings have a sealant applied for extra protection against leaks. Also known as Pressure Class 125 fittings, they are built for use in low-pressure applications.

Low-Pressure Plated Brass Threaded Pipe Fittings

Used in low-pressure pipe lines, these brass fittings have a plating that makes them shiny and improves corrosion resistance.

Extreme-Pressure Brass Threaded Pipe Fittings

Extreme pressures are no problem for these heavy-duty brass fittings.

Low-Pressure Aluminum Threaded Pipe Fittings

In addition to being lightweight, these aluminum fittings offer good corrosion resistance. Use them in low-pressure flow applications.

Medium-Pressure Aluminum Threaded Pipe Fittings

Designed for medium-pressure applications, these fittings have better strength than our low-pressure aluminum pipe fittings.

High-Pressure Aluminum Threaded Pipe Fittings

Also known as Pressure Class 3000 fittings, these have the highest pressure rating of all the aluminum pipe fittings we offer.

Titanium Threaded Pipe Fittings

Titanium has similar strength to steel, but is approximately 40% lighter. It has better corrosion resistance than most stainless steel alloys and can handle corrosive substances, such as salt water and acids.

Plastic Pipe and Pipe Fittings

Drain, Waste, and Vent ABS
Pipe Fittings for Chemicals

These fittings are an economical option for chemical waste systems. Fittings are ABS plastic, which has excellent strength and impact resistance and good chemical resistance.

Aboveground Standard-Wall PVC Pipe
Fittings for Drain, Waste, and Vent

These Schedule 40 fittings are the industry standard for gravity-flow drain, waste, and vent (DWV) applications.

Underground PVC Pipe Fittings
for Drain, Waste, and Vent

With thinner walls than Schedule 40 fittings, these are lighter in weight and have more space on the inside for high-flow applications, such as underground gravity-flow sewer and storm drainage lines. They are also known as SDR 35 fittings.

Threaded Round Plugs for NPT Pipe

Protect internally threaded NPT connections from contaminants during fabrication and storage.

High-Temperature Round Plugs for NPT Pipe

These plugs withstand temperatures up to 600° F to protect internally threaded NPT connections from contaminants during electropainting, paint baking, and powder coating applications.