Caps and Plugs


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Caps and Plugs Samples

Sample Packs

Order a sample pack and find the cap or plug size you need.

Available for any Part Number

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BioMax

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BioMax™

Plant-Based HDPE Caps and Plugs

Available For All Sizes

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Grease Caps

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Grease Caps 

Keep dirt, dust, and debris off your grease fittings between maintenance intervals.

Find the Right Zerk Fitting Caps for Your Equipment

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Caps and Plugs General

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Caps and Plugs

Explore a wide selection of sizes and styles, manufactured right here in the USA.

Factory-Direct. Made to Fit.

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PART FINDER TOOL

Use our Part Finder Tool to search our catalog of caps and plugs by your preferred shape and diameter range.

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Caps and Plugs, Certified Quality

Made in USA

Made in USA

Factory-Direct, We are the Manufacturer.

Recyclable Materials

Recyclable Materials

All products are made from recyclable materials.

Sustainable Options

Sustainable Options

All products can be made with plant-based HDPE.

Free Shipping

Free Shipping

Free Ground Shipping on all orders within the US48.

Plastic Caps / Plastic Plugs

Straight Wall Flanged

Straight Wall Flanged

Reversible plug or cap, features flanges for easy installation and removal.

Straight Wall Flangeless

Straight Wall Flangeless

Fits over threaded and non-threaded tubing, rods, and fittings, forming a flush sealed closure.

Straight Wall Pull Tab

Straight Wall Pull Tab

Straight wall pull tab design for easy removal as a cap or plug.

BioMax™ Sustainable Caps & Plugs

BioMax™ Sustainable Caps & Plugs

Caps and Plugs made with BioMax™ plant-based high-density polyethylene (HDPE).

Tapered Wall Flanged

Tapered Wall Flanged

Reversible plug or cap, features flanges for easy installation and removal. Tapered for tight seal.

Tapered Wall Pull Tab

Tapered Wall Pull Tab

Reversible plug or cap, features flanges for easy installation and removal. Tapered for tight seal.

Grease Caps

Grease Caps

Reversible plug or cap, features flanges for easy installation and removal. Tapered for tight seal.

Any Part, Any Size.

Order Samples!

Find the right fit before you order. Request samples from our range of caps and plugs to check the size, fit, and function for your application. Whether you’re comparing options or have a specific part in mind, our team can help you select samples that meet your needs.

Talk to Our Sales Team

Test samples with your actual components to evaluate how they install, stay in place, and remove. Need help narrowing down your choices? Share your dimensions and application details, and our friendly sales team can help you find a suitable option.

Sample Packs
Plastic Pipe Caps

Top-Quality Material

Plastic Pipe Caps

Explore our comprehensive range of caps and plugs designed specifically for pipe applications. These components cover exposed pipe ends and openings to help keep out dirt, dust, and debris during storage, handling, and shipping. 

Plastic pipe caps also help protect exposed edges and threads from damage caused by everyday contact. Available in multiple sizes and styles, they offer a practical way to keep pipes protected until they’re ready for use or installation.

Keep Dirt Out. Keep Equipment Moving.

Grease Fitting Caps

Protect your grease fittings from dirt, dust, and debris between maintenance intervals. Our grease caps help keep fitting openings clean and ready for lubrication. Explore our available sizes to find the right fit for your equipment.

Protect Lubrication Points with Zerk Fitting Caps

Covering grease fittings helps reduce the buildup of contaminants that could enter during lubrication. A simple addition to your maintenance routine, these caps help protect lubrication points on machinery, vehicles, and other equipment.

Grease Caps

Friendly Sales Team

Real people, ready to help.

Transparent Pricing

Clear prices. No surprises.

Small Quantities Available

Boxes as small as 500 units.

Samples Available

Sample quantities available for all part numbers.

Frequently Asked Questions

What is a cap and plug?

Plastic caps and plugs are protective components used to cover or seal openings in pipes, tubes, fittings, and other industrial products. A cap typically fits over the outside of a component, while a plug fits inside an opening. Both help protect against dust, dirt, moisture, contamination, and damage during manufacturing, shipping, and storage.

Should I use a plug or a cap?

Choose a cap to protect external features like threads and surfaces from environmental damage. Opt for a plug to safeguard internal passages and holes against contamination and debris.

What is a protective cap?

A protective cap is a covering designed to shield exposed components, openings, threads, or sharp edges from damage and contamination. Plastic protective caps are commonly used in manufacturing, automotive, electronics, plumbing, and other industrial applications to protect products during production, transportation, and storage.

Can plastic caps and plugs withstand high temperatures?

Plastic caps and plugs can withstand different temperatures depending on the material and application. Caps and Plugs USA manufactures products using polypropylene (PP) and BioMax™ high-density polyethylene (HDPE). HDPE has a typical melting temperature of approximately 130 degrees Celcius (266 Degrees Fahrenheit), while polypropylene melts at approximately 165 Degrees Celcius (329 Degrees Fahrenheit).

How are plastic caps and plugs made?

Plastic caps are typically made through a process called injection molding. In this process, molten plastic is injected into a mold that is shaped like the desired cap.

What are pipe caps?

Pipe caps are protective covers designed to fit over the ends of pipes, tubing, and fittings. They help prevent dirt, debris, moisture, and other contaminants from entering while protecting exposed ends from damage. Plastic pipe caps are commonly used during manufacturing, shipping, storage, and installation.

What is a pipe cap in plumbing?

A pipe cap is a type of pipe fittings, also known as heads, plugs, bulkheads, installed on the external thread of the pipe end to cover the pipes. Used to close the pipeline, the function is the same as the pipe plug.

What are masking caps?

Masking caps are protective covers used to shield specific areas of components from paint, coatings, or other finishing processes.

How are plastic caps made?

Plastic caps and plugs are commonly manufactured using injection molding. During this process, plastic resin is heated until molten and injected into a precision-engineered mold. Once cooled and solidified, the finished component is ejected from the mold. Injection molding allows for consistent quality, precise dimensions, and efficient high-volume production.

What is the difference between a cap and a plug?

The primary difference is how they fit. A plastic cap covers the outside of a component, while a plastic plug fits inside an opening. Both provide protection and are available in various sizes, shapes, and materials to accommodate different industrial applications.

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