Cookies and audience measurement
We use Google Analytics to measure how the site is used and to improve our content. It only loads with your consent: you can decline at no cost and change your mind at any time. Privacy policy
This post contains affiliate links. As an Amazon Associate we earn from qualifying purchases.
Our picks are based on Amazon bestseller rankings, Amazon customer ratings, and product availability. We update our recommendations regularly to ensure accuracy.
Compression cap fittings are essential for managing fluid lines in various applications, from plumbing to pneumatic systems. Choosing the right fitting ensures leak-free connections and optimal performance. This guide will help you navigate the options to find the most suitable compression cap fittings for your needs.
Package Include: Brass 3/8-inch Comrpression Cap -10Pcs, and suitable Sealing Washer - 10Pcs.
Versatile: Suitable for 3/8'' Comp supply line, plumbing repairs, toilets faucets, Add-A-Tee valve, washing / heater / dishwasher / under kitchen sink valves, and other applications requiring compression fittings.
Special Remarks: It's a 3/8'' compression fitting, NOT 3/8'' NPT thread. Double check your needs, if you need 3/8 NPT, It doesn't meet your requirements. But If you need a 3/8 compression fitting (for sink shut-off valves), then these are perfect.
Easy Installation: Designed for a secure, leak-proof fit with compression fittings.
Package Include: Brass 1/4-inch Comrpression Cap -15Pcs, and suitable Sealing Washer - 15Pcs.
Versatile: Suitable for 1/4'' Comp supply line, plumbing repairs, toilets faucets, Add-A-Tee valve, washing / heater / dishwasher / under kitchen sink valves, and other applications requiring compression fittings.
Special Remarks: It's a 1/4'' compression fitting, NOT 1/4'' NPT thread. Double check your needs, if you need 1/4NPT, It doesn't meet your requirements. But If you need a 1/4'' compression fitting (for sink shut-off valves), then these are perfect.
Easy Installation: Designed for a secure, leak-proof fit with compression fittings.
Introduction: The 40pcs compression caps with 9/16"-24 unef thread are suitable for the outer diameter 3/8 inch of pipes and can be used for gas garden water air hose lines.
Material: Brass. Low magnetic permeability, good ductility and plasticity at high temperatures, higher strength and hardness, able to withstand certain mechanical stress and wear, not easily corroded in humid environments, and not easily damaged during...
Craftsmanship: The 3/8" compression fittings are with fine manufacturing process, smooth surface without burrs, with good polishability and a beautiful golden appearance.
Easy to Use: These gas line caps are easy to assemble, without the need for welding, flaring, or deburring. They can be easily connected to other components through threaded connections, welding, crimping, etc. When it is necessary to replace them, the...
These 1/2 inch brass blanking nut caps effectively seal pipes and valves and come with a sealing washer to prevent leaks in vertical, horizontal, or angled installations.
Made of high-quality brass with a smooth, flat surface, sturdy, durable, rustproof, resistant to corrosion. Its precision thread design ensures a secure connection.
The internal thread diameter is about 19mm and the external diameter is 25mm. TIP: Please check the size before ordering. The hex head design allows for easy installation and removal by hand or with a regular wrench.
The brass cap is compatible with a wide range of pipes and valves. Suitable for washing machines, dishwashers, radiators, and faucets.
Package Include: Brass 3/8-inch Comrpression Cap -25Pcs, and suitable Sealing Washer - 25Pcs.
Versatile: Suitable for 3/8'' Comp supply line, plumbing repairs, toilets faucets, Add-A-Tee valve, washing / heater / dishwasher / under kitchen sink valves, and other applications requiring compression fittings.
Special Remarks: It's a 3/8'' compression fitting, NOT 3/8'' NPT thread. Double check your needs, if you need 3/8 NPT, It doesn't meet your requirements. But If you need a 3/8 compression fitting (for sink shut-off valves), then these are perfect.
Easy Installation: Designed for a secure, leak-proof fit with compression fittings.
Sufficient Quantity: you will receive 100 pcs 3/8 compression caps, providing sufficient quantity for you to seek to optimize cost ratio; This large quantity ensures that you are equipped even for larger projects or frequent needs, while also providing a...
Size Information: the compression caps come in a size of about 3/8 inches, offering a better fit for various applications; This size ensures a snug fit for a wide range of uses, eliminating any room for leaks; Products that are easy to install and remove...
Brass Material: experience the nice ductility and durability of the brass compression fittings; Made of quality brass material, their longevity even under strenuous usage conditions is a testament to their nice quality and robustness
Use with Washers: these compression caps are designed to be applied with washers for seamless functionality; The ease of usage serves as an advantage as you can conveniently execute your repair, installation or maintenance tasks without encountering...
Package Content: The package includes 6 end pipe caps and 6 rubber washers gaskets to prevent leaks, ensuring a tight fit for air, water, or gas lines. Enough quantity to satisfy your use needs.Please check the size details to ensure it fit yours before...
Versatile Applications: Durable and high standard brass plug hex head end pipe caps. Our pipe caps are frequently utilized in irrigation, underground sprinkler systems, swimming pools, plumbing fixtures, and rainwater collection systems, among others.
Product Details: Size: Inner diameter 0.51in/13mm, outer 0.67in/17mm, height 0.35in/9mm. Our cap fits 1/4-inch NPT female pipe caps, designed for 1/4in closing the end of pipes or fittings.The cap BODY is larger than the thread size – please measure...
Easy to Use: Each pipe cap is designed with a hex head and internal thread, easy to close the end of the pipes, and it is easy to detach.
Last update on 2026-10-14 / Affiliate links / Images from Amazon Product Advertising API
How to Choose the Best Compression Cap Fittings
Installation and Maintenance Tips
Proper installation is key to a reliable seal. Ensure the tube end is clean, cut squarely, and free of burrs. Slide the nut onto the tube, followed by the ferrule. Insert the tube into the fitting body, then tighten the nut onto the fitting body. Overtightening can damage the ferrule or tube, while undertightening will result in leaks. Periodically check for any signs of leakage, especially if system pressure or temperature fluctuates.
Frequently Asked Questions
What is the difference between a ferrule and a nut in a compression fitting?
The nut is the component you tighten, which forces the ferrule against the tube. The ferrule is the ring that deforms and creates the seal between the tube and the fitting body.
Can I reuse a compression cap fitting?
It is generally not recommended to reuse compression fittings, especially the ferrule. The ferrule deforms during the initial tightening to create a seal, and reusing it may compromise the integrity of the connection.
What type of tubing is compatible with compression fittings?
Compression fittings are designed for use with soft copper, aluminum, or plastic tubing. The tubing must have a consistent outer diameter and be rigid enough to support the ferrule's compression.
How do I determine the correct size fitting?
The size of a compression fitting refers to the outside diameter of the tubing or pipe it is designed to connect. Measure the outside diameter of your tubing to select the appropriately sized fitting.
Are plastic compression fittings suitable for gas lines?
Plastic compression fittings are typically not recommended for gas lines due to potential compatibility issues and lower pressure ratings. Brass or stainless steel fittings are usually preferred for gas applications.
What causes a compression fitting to leak?
Leaks can occur from undertightening, overtightening which deforms the ferrule or tube, using the wrong size fitting, or if the tubing surface is damaged or not properly prepared.
As an Amazon Associate, we earn from qualifying purchases. Product prices and availability are accurate as of the date/time indicated and are subject to change.
Before You Go!
Get the latest deals and product comparisons delivered to your inbox.
