Best Union Tube Nuts in 2026
Daisy
Last Updated: Jul 17, 2026
Daisy
Last Updated: Jul 17, 2026
* PickSmartly editors independently research, review, and endorse the top products through comprehensive data analysis. We may earn a commission for qualifying purchases made through our product links.
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| Fiada US | 9.93 | ✅ | ✅ | ✅ |
Fit for: the unions measures approx. 0.6 x 0.9 inch, the nut measures approx. 0.67 x 3/8 inch, fit for most common inverted flare or double flare sizes for 3/16 inch tube, for use with 3/16 inch steel, poly coated or copper brake lines; Please confirm the size of the details according to the picture before purchasing
Size and material: both the unions and nuts are metric 3/8-24 threads (regular 3/16 inch tube fitting size), all brake line fittings are made of quality brass to prevent rust and plated for corrosion resistance
You will get: 12 pieces brake line fittings in the package, include 4 pieces unions and 8 pieces nuts, you can share them with your family and friends, these tubes unions are good fittings
Inverted flare union: these unions are a nice option to join 2 (3/16 inch) brake lines together
Brake line fitting connect: the nut is called the fitting for 3/16 inch tube, these unions fittings have a hex size of 3/8 inch and the threads are 3/8 inch with a thread pitch of 24
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| Litorange | 9.84 | ✅ | ✅ | ✅ |
★ 【Material】: Heavy Duty Brass,strong and durable. Dual couplings for joining two tubes of the same diameter(OD: Outer Diameter).
★ 【Firm And Durable】: Litorange Brass for corrosion resistance, high temperature ductility and low magnetic permeability.
★ 【Function】: Union for connecting and disconnecting two tubes more easily than with a coupling
★ 【Tips】: For low to medium pressure operating environments with no excessive vibration or tube movement. Use with copper, brass, aluminum, or plastic tubing
★ 【Package Include】: 3 PCS 1/4" x 1/4" Tube OD. (include nuts and ferrules)
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| Amazon.com | 9.68 | ✅ | ✅ | ✅ |
Three piece construction - nut, sleeve and body with attached insert
Use with copper, brass, aluminum, or plastic tubing
Standard fittings use short nuts
Easy to disassemble no flaring tool required
Primary uses water, gasoline, oil and vacuum lines
These fittings contain lead and are not allowed by federal law to be installed for potable water use in the U.S.A. and its territories.
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| Amazon.com | 9.68 | ✅ | ✅ | ✅ |
Half union for connecting and disconnecting two tubes more easily than with a coupling
45-degree flare head tube connection on one side and a male NPT connection on the other
Brass for corrosion resistance, ductility at high temperatures, and low magnetic permeability
Operating temperature range of -65 to +250 degrees F
Resists mechanical pullout for a more secure connection
These fittings contain lead and are not allowed by federal law to be installed for potable water use in the U.S.A. and its territories.
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| Legines | 9.70 | ✅ | ✅ | ✅ |
Three piece construction - nut, sleeve and body with attached insert Use with copper, brass, aluminum, or plastic tubing
Manufactured for low and medium pressure tubing connection work where excessive vibration or tube movement is not involved.
Use with copper,aluminum and thermoplastic tub-ing.Not recommended for steel tubing.
Not recommended for application using gas eous media.
Meets specifications and standards of ASA, ASME asn SAE.
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| Horiznext | 9.86 | ✅ | ✅ | ✅ |
Made of stainless steel 304, heavy duty, durable and corrosion resistant.
1/4" outer diameter tube
Fittings for connecting and extending stainless steel, copper, rigid and semi-rigid plastic tubing
Maximum working pressure of 600 psi
Temperature range from -100 to +660 degrees ℉
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| MuHize® Direct | 9.85 | ✅ | ✅ | ✅ |
PACKAGE INCLUDE - MuHize upgraded Brake Line Fittings Replacement (Pack of 15): ① 5 x 3/8-24 threads unions; ② 10 x 3/8-24 threads nuts. Note：Both the unions and nuts are 3/8-24 threads (regular 3/16 inch tube fitting size). Please check before shopping!
INVERTED FLARE UNION- Any 2 (3/16 inch) brake lines can be easy to joined with Muhize unions. both the sizes for unions and nuts are both 3/8-24 threads, which is the regular fitting size for 3/16 inch tube.
HIGHER QUALITY - MuHize brake line fittings are made of durable brass with unique rust corrosion proofing technology.
WIDELY APPLICATION - MuHize 3/8' - 24 threads fittings commonly fits for regular inverted flare/ double flare sizes for 3/16 inch brake lines tube.
PROFESSIONAL - MuHize focus on outstanding features and benefits of braking line. 100% brand new & made from excellent materials, and good contact.
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| MuHize® Direct | 9.85 | ✅ | ✅ | ✅ |
PACKAGE INCLUDE - MuHize upgraded Brake Fittings Replacement (Pack of 15): ① 5 x 3/8-24 threads unions; ② 10 x 3/8-24 threads nuts. Note：Both the unions and nuts is 3/8-24 threads (regular 3/16 inch tube fitting size) . Please check before shopping!
INVERTED FLARE UNION- Any 2 (3/16 inch) brake lines can be easy to joined with Muhize unions. both the sizes for unions and nuts are both 3/8-24 threads, which is the regular brake fitting size for 3/16 inch tube.
HIGHER QUALITY - MuHize brake fittings are made of durable brass with unique rust corrosion proofing technology.
WIDELY APPLICATION - MuHize 3/8' - 24 threads fittings commonly fits for regular inverted flare/ double flare sizes for 3/16 inch brake lines tube.
PROFESSIONAL - MuHize focus on outstanding features and benefits of braking line. 100% brand new & made from excellent materials, and good contact.
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| Gasher | 9.91 | ✅ | ✅ | ✅ |
SIZE: 1/4” Flare x 1/4“ Flare
EASY TO INSTALL: no need to resort to other tools, convenient for connection and disassembly
DURABLE: High grade brass construction for corrosion resistance, high temperature ductility and low magnetic permeability
FUNCTION: Half union for connecting and disconnecting two tubes more easily than with a coupling
PACKAGE INCLUDES: 4 × 1/4" Connectors, 8 × 1/4" Flare Nuts.
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| timsec | 9.85 | ✅ | ✅ | ✅ |
[100% BRASS ADAPTER] - The AC pipe joint connectors are all made by heavy duty brass, sturdy, durable, corrosion resistant and anti-rust.
[SPECIFICATION] - Fit for copper pipe Diameter 1/4" (6.35mm).
[APPLICATION] - The AC pipe jointers are designed to connect two copper pipes without welding. The connection can be tightened with a wrench, sturdy and durable. This flare fittings can also be applied in fuel and gas systems, plumbing, refrigeration, and vacuum applications.
[EASY TO INSTALL] - The joint is used to lengthen the AC copper tubes. The DIY projects can be finished by household tools without a special welding machine.
[PACKAGE INCLUDES] – The package includes 2pcs solid brass connectors and 4pcs Flare Nuts.
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| CHILLWAVES | 7.35 | ✅ | ✅ | ✅ |
SIZE - 1/4" Tube OD x 1/4" Tube OD, Compression Tube Fitting mainly consists of a fitting body with a 24 degree tapered hole, a ferrule with a sharp inner edge, and a nut for compression.
MATERIAL - Made of high-quality brass, with strong wear and corrosion resistance, high compressive strength, durability, low magnetic permeability and high temperature ductility.
Use - Suitable for oil, gas, water and other non-corrosive or corrosive pipeline systems, temperature and pressure resistance, good sealing and repeatability, no need for welding and flaring tools, easy disassembly, installation and maintenance, etc.
WORKING PRESSURE & TEMPERATURE - 1200PSI maximum working pressure, temperature range -65°F to +250°F (-53°C to +121°C)
WORKING PRINCIPLE - Compression Tube Fitting is to compress the ferrule by thread interlocking, and the two ends of the inner diameter of the ferrule tightly wrap the tube due to radial shrinkage, which plays a sealing role and realizes the sealing and tightening effect between the joint and the tube.
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| CHILLWAVES | 7.16 | ✅ | ✅ | ✅ |
SIZE - 1/4" Tube OD x 1/4" Tube OD x 1/4" Tube OD, Compression Tube Fitting mainly consists of a fitting body with a 24 degree tapered hole, a ferrule with a sharp inner edge, and a nut for compression.
MATERIAL - Made of high-quality brass, with strong wear and corrosion resistance, high compressive strength, durability, low magnetic permeability and high temperature ductility.
Use - Suitable for oil, gas, water and other non-corrosive or corrosive pipeline systems, temperature and pressure resistance, good sealing and repeatability, no need for welding and flaring tools, easy disassembly, installation and maintenance, etc.
WORKING PRESSURE & TEMPERATURE - 1200PSI maximum working pressure, temperature range -65°F to +250°F (-53°C to +121°C)
WORKING PRINCIPLE - Compression Tube Fitting is to compress the ferrule by thread interlocking, and the two ends of the inner diameter of the ferrule tightly wrap the tube due to radial shrinkage, which plays a sealing role and realizes the sealing and tightening effect between the joint and the tube.
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| caosunshangmao | 9.91 | ✅ | ✅ | ✅ |
Material: All brake pipe fittings are made of high-quality brass to prevent rust and plated to prevent corrosion.
3/16" Brake Line Fittings: 15 Fittings for 3/16" Brake Line: 5 x 3/8-24 threads unions; 10 x metric 3/8-24 threads nuts.
Size: The threads are 3/8 inch with a thread pitch of 24.
Inverted flare union: These connectors are a good choice for connecting 2 (3/16 inch) brake lines together.
Application: This brake line nut is suitable for inverted bellmouth on 3/16 inch Tube.
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| Best Hardware Direct | 8.03 | ✅ | ✅ | ✅ |
Package Qty : 1 Piece Fitting + 2 Nuts
Material : Copper
Size : 3/8"
Application: Air Conditioning Copper Pipe
Sturdy and Durable, and are not easily damaged when installed.
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| LTWHOME | 5.17 | ❌ | ❌ | ❌ |
Type: Female 45 Deg flare swivel nut union
Hose ID: 1/4"
Swivel Nut: 3/8" Female
Materies: BRASS
Muti-functional using:connecting lines for air, water, fuel, oil and inert gases
| SELLER | SELLER SCORE | AMAZON FULFILLED | PRIME | FREE SHIPPING |
|---|---|---|---|---|
| KRD PERFORMANCE | 7.71 | ✅ | ✅ | ✅ |
Size: -6AN Male to -6AN Male With AN6 O-ring, 90 degree
Material: CNC-machined of lightweight 6061-T6 billet aluminum
Finish: black anodized for durability and strength
Application: great for any liquid or gas application where a high-flow splitter is needed
Forged swivel elbow design
Here is the list of top-rated brands that were evaluated by PM.
| Brand | Count |
|---|---|
| Anderson Metals | 2 |
| Chillwaves | 2 |
| Muhize | 2 |
| Frienda | 1 |
| Gasher | 1 |
| Hongbow Hardware | 1 |
| Horiznext | 1 |
| Krd Performance | 1 |
| Legines | 1 |
| Litorange | 1 |
We've carried out a comprehensive analysis of 3,776 reviews on union tube nuts, using our selection criteria to identify the best options in the automotive replacement parts. Our findings reveal that most customers typically select union tube nuts priced around $10.98, with top brands including krd performance, anderson metals, jaco manufacturing, legines, gasher, yoebor, horiznext, ltwfitting and tl toolegin and meter star
Our team of expert editors reviewed these high-quality items and handpicked the top 16 union tube nuts for your consideration. We've also done extensive research on numerous sellers, identifying the best ones in the automotive replacement parts category. These include krd performance, amazon.com, isopure_water, legines, gasher, metalwork, horiznext, honest-f and meichi and ltwhome .
We are dedicated to assisting our users in finding the right fittings Products based on their needs, saving them considerable time when choosing which union tube nuts to buy. We take pride in the number of satisfied users we've helped through our thorough and insightful reviews.
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