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.
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Ultra-High-Polish Gasket Fittings for Stainless Steel Tubing

- For Use With: Ammonia, Argon, Butane, Carbon Dioxide, Chloride, Fluoride, Fluorocarbon, Germane, Halide, Helium, Hydrogen, Krypton, Laser Gas, Natural Gas, Neon, Nitrogen, Oxygen, Silane, Sulfur Hexafluoride, Tungsten Hexafluoride, Xenon
- Temperature Range: -420° to 1000° F
- Tubing: Use with 316/316L stainless steel
- Compatible With: Swagelok® VCR
Polished to at least a 15 Ra finish on the inside, these fittings have an ultra-smooth interior surface that helps prevent contamination. Also known as ultra-high-purity fittings, they’re packed in a Class 100 clean room, cleaned, and double bagged. They are commonly used in semiconductor applications. Fittings use a metal gasket (sold separately), which generates fewer particles than a rubber gasket and creates a strong seal in high-pressure and high-vacuum applications. Fittings are 316 stainless steel for excellent corrosion resistance.
To assemble, place a gasket between the gasket ends before gently rotating the female-threaded fitting onto the male-threaded fitting. Tighten until 1/8 of a turn past finger tight.
Choose threaded fittings to attach directly to other fittings. Or, choose one of the following types of fittings to attach directly to tubing:
Butt-weld fittings allow for a smooth, flush connection that provides maximum flow.
Yor-Lok fittings have two sleeves that bite into tubing as you tighten the nut, creating a strong steal without the need for welding. They're also known as instrumentation fittings.
Tube stem fittings connect to Yor-Lok fittings (sold separately).
For technical drawings and 3-D models, click on a part number.

For Tube OD (A) | For Tube OD (B) | Material | Max. Pressure | Max. Vacuum | Interior Smoothness, Ra | Environmental Rating | Each | |
1/2" | 1/4" | 316L Stainless Steel | 3,750 psi @ 72° F | 10 -11 torr @ 72° F | 5 | Fed. Std. Class 100 | 00000000 | 000000 |

For Tube (Yor-Lok) | |||||||||
---|---|---|---|---|---|---|---|---|---|
For Tube OD (Gasket) | OD | Wall Thick. | Material | Max. Pressure | Max. Vacuum | Interior Smoothness, Ra | Environmental Rating | Each | |
1/4" | 1/8" | 0.035" | 316L Stainless Steel | 5,100 psi @ 72° F | 10 -11 torr @ 72° F | 5 | Fed. Std. Class 100 | 00000000 | 000000 |
1/4" | 3/8" | 0.035" | 316L Stainless Steel | 5,100 psi @ 72° F | 10 -11 torr @ 72° F | 5 | Fed. Std. Class 100 | 00000000 | 00000 |

Adapters with an unthreaded gasket fitting connection are also known as glands.
For Tube OD | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Gasket | Butt Weld | Wall Thick. | Lg. | Material | Max. Pressure | Max. Vacuum | Interior Smoothness, Ra | Environmental Rating | Each | |
1/4" | 1/8" | 0.028" | 1 3/32" | 316L Stainless Steel | 5,100 psi @ 72° F | 10 -11 torr @ 72° F | 5 | Fed. Std. Class 100 | 00000000 | 000000 |
1/4" | 1/8" | 0.028" | 1 13/32" | 316L Stainless Steel | 5,100 psi @ 72° F | 10 -11 torr @ 72° F | 5 | Fed. Std. Class 100 | 00000000 | 00000 |
1/2" | 1/4" | 0.035" | 1 1/8" | 316L Stainless Steel | 3,750 psi @ 72° F | 10 -11 torr @ 72° F | 5 | Fed. Std. Class 100 | 00000000 | 00000 |
1/2" | 1/4" | 0.035" | 1 25/32" | 316L Stainless Steel | 3,750 psi @ 72° F | 10 -11 torr @ 72° F | 5 | Fed. Std. Class 100 | 00000000 | 00000 |
1/2" | 3/8" | 0.035" | 1 1/8" | 316L Stainless Steel | 3,750 psi @ 72° F | 10 -11 torr @ 72° F | 5 | Fed. Std. Class 100 | 00000000 | 00000 |
1/2" | 3/8" | 0.035" | 1 25/32" | 316L Stainless Steel | 3,750 psi @ 72° F | 10 -11 torr @ 72° F | 5 | Fed. Std. Class 100 | 00000000 | 00000 |

Adapters with an unthreaded gasket fitting connection are also known as glands.
For Tube OD (Gasket) | Tube Stem OD | Wall Thick. | Material | Max. Pressure | Max. Vacuum | Interior Smoothness, Ra | Environmental Rating | Each | |
1/2" | 3/8" | 0.049" | 316L Stainless Steel | 3,750 psi @ 72° F | 10 -11 torr @ 72° F | 5 | Fed. Std. Class 100 | 00000000 | 000000 |


For Tube OD | Nut Material | Max. Pressure | Max. Vacuum | Lg. | Each | |
Male | ||||||
---|---|---|---|---|---|---|
1/4" | 316L Stainless Steel | 5,100 psi @ 72° F | 10 -11 torr @ 72° F | 17/32" | 00000000 | 00000 |
1/4" | 316L Stainless Steel | 5,100 psi @ 72° F | 10 -11 torr @ 72° F | 23/32" | 0000000 | 0000 |
1/2" | 316L Stainless Steel | 3,500 psi @ 72° F | 10 -11 torr @ 72° F | 13/16" | 0000000 | 00000 |
Female | ||||||
1/4" | 316L Stainless Steel | 5,100 psi @ 72° F | 10 -11 torr @ 72° F | 13/16" | 0000000 | 0000 |
1/2" | 316L Stainless Steel | 3,500 psi @ 72° F | 10 -11 torr @ 72° F | 7/8" | 0000000 | 00000 |


Retaining
Tabs
Nickel gaskets are softer than stainless steel gaskets, so they won’t wear down sealing surfaces as much, and they’re easier to tighten. They’re reactive to carbon monoxide and ozone, so they shouldn’t be used with those chemicals.
Hard and heat resistant, stainless steel gaskets can be used in a wider range of applications than nickel gaskets such as carbon monoxide and ozone. However, they’re harder to tighten than nickel gaskets, and they’ll wear down sealing surfaces more quickly.
Silver-plated stainless steel gaskets are softer than unfinished stainless steel gaskets, so they won’t wear down sealing surfaces as much, and they’re easier to tighten. However, they oxidize when exposed to air, and silver particles might flake off during assembly.
Gaskets with retaining tabs stay in place during installation, so you don’t have to hold the gasket while fastening fittings together. This also means they’re less likely to scratch or nick your fittings by rotating during installation.
For Tube OD | Max. Vacuum | Environmental Rating | Each | |
Nickel Gasket | ||||
---|---|---|---|---|
1/4" | 10 -11 torr @ 72° F | Fed. Std. Class 100 | 00000000 | 00000 |
1/2" | 10 -11 torr @ 72° F | Fed. Std. Class 100 | 00000000 | 0000 |
316L Stainless Steel Gasket | ||||
1/4" | 10 -11 torr @ 72° F | Fed. Std. Class 100 | 0000000 | 0000 |
1/2" | 10 -11 torr @ 72° F | Fed. Std. Class 100 | 0000000 | 0000 |
Silver-Plated 316L Stainless Steel Gasket | ||||
1/4" | 10 -11 torr @ 72° F | Fed. Std. Class 100 | 00000000 | 0000 |
1/2" | 10 -11 torr @ 72° F | Fed. Std. Class 100 | 00000000 | 0000 |
316L Stainless Steel Gasket with Retaining Tabs | ||||
1/4" | 10 -11 torr @ 72° F | Fed. Std. Class 100 | 00000000 | 0000 |
1/2" | 10 -11 torr @ 72° F | Fed. Std. Class 100 | 00000000 | 0000 |
Easy-Read Tank-Mount Pressure-Regulating
Valves with Flowmeter for Inert Gas


Flowmeters let you see the gas flow rate from a distance. These valves automatically reduce a high inlet pressure from compressed gas tanks to a lower, stable outlet pressure. All have Compressed Gas Association (CGA) numbered inlet fittings for secure connections to compressed gas tanks. Choose a valve with the same CGA number as your tank and other system components. They have a gauge for monitoring inlet pressure from the tank.
Single-stage valves reduce pressure in one step, which causes the outlet pressure to fluctuate slightly as you empty the tank. They’re best for applications where a constant outlet pressure isn’t critical.
Valves with one flowmeter are for one piece of equipment on a tank. The flowmeter has a single scale.
Adapters (sold separately) change 5/8"-18 outlets to 9/16"-18 male connections, and vice versa.
Inlet | Outlet | Material | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
CGA Number | Location | Thread Direction | Pressure Gauge Range, psi | Stage | Thread Size | Location | Thread Direction | Flow Range, scfh | Number of Flowmeters | Body | Seal | Diaphragm | Each | |
UNF Female Outlet × NGO Male Inlet | ||||||||||||||
CGA 580 | Side | Right Hand | 0 to 4,000 | Single | 5/8"-18 | Side | Right Hand | 0 to 100 (Helium), 0 to 140 (Hydrogen) | 1 | Brass | PTFE | Neoprene | 000000000 | 0000000 |
Optional Adapter | 00000000 | Each | 000000 |
Inlet | Outlet | Material | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
CGA Number | Location | Thread Direction | Pressure Gauge Range, psi | Stage | Thread Size | Location | Thread Direction | Flow Range, scfh | Number of Flowmeters | Body | Seal | Diaphragm | Each | |
UNF Male Outlet × NGO Female Inlet | ||||||||||||||
CGA 350 | Side | Left Hand | 0 to 3,000 | Single | 9/16"-18 | Side | Left Hand | 0 to 40 | 1 | Brass | PTFE | Neoprene | 000000000 | 0000000 |
Optional Adapter | 00000000 | Each | 000000 |
Pressure-Regulating Valves for Fuel Gases

- For Use With: See Table
- Temperature Range: See Table
Install these valves directly in gas distribution pipelines for acetylene, hydrogen, or propane. They automatically reduce a high inlet pressure to a lower, stable outlet pressure. Valves have two outlets to fit various pipe configurations and come with a plug to close the unused outlet. The gauge monitors outlet pressure. All valves are single stage and reduce pressure in one step, which causes the outlet pressure to fluctuate.
Choose a valve with a maximum outlet pressure that’s approximately twice your application’s normal operating pressure. Your operating pressure should never exceed 75% of the valve’s maximum outlet pressure.
Inlet | Outlet | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
For Use With | Pipe Size | Location | Max. Pressure, psi | Pipe Size | Location | Pressure Adjustment Method | Pressure Gauge Range, psi | Temperature Range, ° F | End-to-End Lg. | Port-to-Port Lg. | Each | |
NPT Female | ||||||||||||
Brass Body—Stainless Steel Diaphragm and Neoprene Seal | ||||||||||||
Hydrogen, Propane | 1/4 | Side | 500 | 1/4 | Bottom, Side | T-Handle | 0 to 60 | 0° to 120° | 2.40" | 1.01" | 0000000 | 0000000 |
Hydrogen, Propane | 1/4 | Side | 500 | 1/4 | Bottom, Side | T-Handle | 0 to 200 | 0° to 120° | 2.40" | 1.01" | 0000000 | 000000 |
Tank-Mount Pressure-Regulating Valves for Fuel Gases
- For Use With: See Table
- Temperature Range: -20° to 120° F
Attach these valves to acetylene, hydrogen, methane, propane, or propylene tanks to reduce a high inlet pressure to a lower, stable outlet pressure. They have Compressed Gas Association (CGA) numbered inlet fittings for secure connections to compressed gas tanks. Choose a valve with the same CGA number as your tank and other system components. Valves come with a gauge to monitor outlet pressure and a gauge to monitor inlet pressure from the tank.
Choose a valve with a maximum outlet pressure that’s approximately twice your application’s normal operating pressure. Your operating pressure should never exceed 75% of the valve’s maximum outlet pressure.
Single-stage valves reduce pressure in one step, which causes the outlet pressure to fluctuate slightly as you empty the tank. They’re best for applications where a constant outlet pressure isn’t critical.
Two-stage valves progressively reduce pressure over two steps for more consistent outlet pressure at all times. They’re often used in applications that require a constant outlet pressure regardless of the tank level.
Valves with a brass body have a longer service life than valves with a brass and steel body.

Inlet | Outlet | Material | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
CGA Number | Location | Thread Direction | Pressure Gauge Range, psi | Thread Size | Location | Thread Direction | Pressure Range, psi | Pressure Adjustment Method | Body | Seal | Diaphragm | Each | |
For Use With Hydrogen | |||||||||||||
UNF Male Outlet × NGO Female Inlet | |||||||||||||
CGA 350 | Side | Left Hand | 0 to 4,000 | 9/16"-18 | Side | Left Hand | 0 to 125 | T-Handle | Brass | PTFE | Rubber | 000000 | 0000000 |

Inlet | Outlet | Material | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
CGA Number | Location | Thread Direction | Pressure Gauge Range, psi | Thread Size | Location | Thread Direction | Pressure Range, psi | Body | Seal | Diaphragm | Each | |
For Use With Hydrogen and Methane | ||||||||||||
UNF Male Outlet × NGO Female Inlet | ||||||||||||
CGA 350 | Side | Left Hand | 0 to 4,000 | 9/16"-18 | Side | Left Hand | 2 to 40 | Brass | Neoprene | Rubber | 0000000 | 0000000 |
High-Purity Tank-Mount Pressure-Regulating Valves for Fuel Gases


- For Use With: Hydrogen, Methane
- Temperature Range: -20° to 120° F
Designed to reduce contaminants in high-purity applications using hydrogen and methane gas, these valves have a stainless steel and brass body with a smooth finish to reduce dust collection and internal components designed to protect the seal and diaphragm from contamination. They’re often used in research sample systems, emission monitoring systems, and chromatography. Valves automatically reduce a high inlet pressure from compressed gas tanks to a lower, stable outlet pressure. All have Compressed Gas Association (CGA) numbered inlet fittings for secure connections to compressed gas tanks. Choose a valve with the same CGA number as your tank and other system components. Outlet fittings are Swagelok® for a leak-free seal around hard metal tubing in high-pressure lines. Also known as instrumentation fittings, Swagelok® fittings are compatible with Parker A-Lok, Gyrolok, Bilok, and Tylok fittings. Valves come with a gauge to monitor outlet pressure and a gauge to monitor inlet pressure from the tank.
Choose a valve with a maximum outlet pressure that’s approximately twice your application’s normal operating pressure. Your operating pressure should never exceed 75% of the valve’s maximum outlet pressure.
Single-stage valves reduce pressure in one step, which causes the outlet pressure to fluctuate slightly as you empty the tank. They’re best for applications where a constant outlet pressure isn’t critical.
Two-stage valves progressively reduce pressure over two steps for more consistent outlet pressure at all times. They’re often used in applications that require a constant outlet pressure regardless of the tank level.
Inlet | Outlet | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
CGA Number | Location | Thread Direction | Pressure Gauge Range, psi | Stage | For Tube OD | Location | Pressure Range, psi | Pressure Adjustment Method | Each | |
Swagelok® Female Outlet × NGO Female Inlet | ||||||||||
Brass/Stainless Steel Body—316 Stainless Steel Diaphragm and PTFE Seal with Relief Valve | ||||||||||
CGA 350 | Side | Left Hand | 0 to 4,000 | Single | 1/4" | Side | 0 to 15 | Knob | 0000000 | 0000000 |
CGA 350 | Side | Left Hand | 0 to 4,000 | Single | 1/4" | Side | 0 to 125 | Knob | 0000000 | 000000 |
CGA 350 | Side | Left Hand | 0 to 4,000 | Two | 1/4" | Side | 0 to 15 | Knob | 0000000 | 000000 |
CGA 350 | Side | Left Hand | 0 to 4,000 | Two | 1/4" | Side | 0 to 125 | Knob | 0000000 | 000000 |
CGA 350 | Side | Left Hand | 0 to 4,000 | Two | 1/4" | Side | 0 to 500 | Knob | 0000000 | 000000 |