Unions, Tees & Crosses

Idex Unions, Tees & Crosses provide dependable fluidic connections for analytical and laboratory applications where precision, chemical resistance, and low dead volume are critical. Designed for chromatography, microfluidics, and general lab plumbing, these high-performance fittings ensure secure connections while maintaining optimal flow paths. Whether you’re building complex manifolds, routing tubing through tight spaces, or splitting flow streams, Idex offers a complete portfolio of engineered solutions to meet your system requirements.

Product Categories

Large Bore Unions

Our Large Bore Union Assemblies are designed specifically to be used with our standard 1/2-20 Flat-Bottom threaded nuts and ferrules. Our unions can create a true zero dead volume (ZDV) connection when partnered with Quick Luer Adapters and the appropriate ferrule. Manufactured from biocompatible PEEK giving is excellent chemical resistance to virtually all commonly used solvents.

Manifolds

Choose a 5, 7, or 9 Port Manifold to combine several streams into one, or split one fluid stream into several. Each PEEK manifold comes complete with 1/4-28 Super Flangeless™ Fittings for either 1/16” or 1/8” OD tubing, with pressure ratings of 2,000 psi (138 bar) and 500 psi (34 bar), respectively. Our PEEK Manifolds are ideal for use in multiport mixing chambers, for gas sparging splitting unions and for sample injection onto multi-well plates or a multiple direction flow path unions.

Elbow Connectors

Our versatile Elbow Connectors are designed to easily navigate tight corners. One Elbow is designed for use with 1/16” OD tubing and has a 0.020” (0.50 mm) thru-hole. Use 1/8” OD tubing with the other Elbow, which has a 0.062” (1.6 mm) thru-hole. Complete with 1/4-28 PEEK nuts and ETFE ferrules and are pressure rated to 1,000 psi (69 bar) these connectors deliver excellent chemical resistance and are ideal for low pressure applications.

Bulkhead Unions

Bulkhead Unions are optimally designed to directly thread through your equipment housing to connect internal tubing to the outside. Each union has unique 3/8-24 external threads and comes complete with a stainless steel nut and lock washer to hold it in place. It requires a 3/8” hole to mount. The recommended torque limit for these unions is 15 in.– lbs (1.7 N·m).

Y Connectors

PEEK Y Connectors are designed to split a stream or join two streams together, just like a tee. However, the configuration of a tee can lead to turbulent flow and solvent outgassing, which increases baseline noise and reduces sensitivity. The geometry of a Y connector creates less turbulence and thus can improve analytical results. All of these Y Connectors use 1/4-28 Flangeless fittings, except P-515 which uses 5/16-24 fittings (to accommodate larger tubing).

Metric Unions

Our low pressure Metric Unions efficiently connects tubing in low pressure regions of a system where a dependable connection is imperative. Our union provides true ZDV which lets tubing to join together without interrupting the fluidic path.

Standard Unions

Our low pressure Standard Unions efficiently connects tubing in low pressure regions of a system where a dependable connection is imperative. Our union provides true ZDV which lets tubing to join together without interrupting the fluidic path.

Union Assemblies

Low Pressure Unions are available in a variety of polymers, providing several low-cost and chemically-resistant options. Manufactured from PEEK, Tefzel (ETFE), Derlin, polypropylene or PCTFE our unions deliver excellent chemical resistance. These versatile unions are available with ¼-28, M6 or 10-32 flat bottom threads.

Tee & Crosses

Low Pressure Tees and Crosses offer a unique design for joining multiple tubing and fittings together. They are available in two inert polymers and can handle pressures to 500 psi (34 bar) or 1,000 psi (69 bar), depending upon the configuration of the products. Our Tees & Crosses are designed with handy mounting holes. All ETFE Tees and Crosses ship complete with 1/4-28 PFA Flangeless nuts and ETFE ferrules, while their PEEK polymer counterparts ship with 1/4-28 PEEK nuts and ETFE ferrules.

VHP Stainless Steel ZDV Unions

These very high pressure, zero-dead-volume (ZDV) unions are precision machined from 316 stainless steel, carefully passivated, then thoroughly rinsed. Each comes complete with stainless steel nuts and ferrules. It is supplied with fittings for 1/16” OD or 1/8” OD tubing. Union assemblies have a pressure rating of 20,000 psi (1,380 bar) or higher.

VHP Tees & Crosses

Our VHP Stainless Steel Tees and Crosses are precision machined from durable stainless steel. It is mechanically designed for bringing together three or four pieces of tubing. Our VHP Tees & Crosses have an extremely high pressure rating of 30,000 psi (2070 bar).

PART NO	DESCRIPTION	TUBING OD	THREADS	THRU-HOLE	SWEPT VOL.	PRESSURE	MATERIAL	COLOR

PEEK UNION ASSEMBLIES
P-702	Union	1/16"	1/4-28 Flat Btm	0.020" (0.50 mm)	0.41 µL	1,000 PSI (69 bar)	PEEK	Natural
P-703	Union	1/16"	1/4-28 Flat Btm	0.050" (1.25 mm)	2.57 µL	1,000 PSI (69 bar)	PEEK	Natural
P-779	NanoTight Union	—	10-32	0.005" (1.25 mm)	8.0 µL	5,000 PSI (345 bar)	PEEK	Natural
ETFE UNION ASSEMBLIES
P-630	True ZDV Union	1/16"	1/4-28 Flat Btm	N/A	N/A	1,000 PSI (69 bar)	ETFE	Natural
P-631	True ZDV Union	1/8"	1/4-28 Flat Btm	N/A	N/A	1,000 PSI (69 bar)	ETFE	Natural
P-710	Union	1/16"	1/4-28 Flat Btm	0.030" (0.75 mm)	0.93 µL	1,000 PSI (69 bar)	ETFE	Natural
STANDARD UNIONS
P-603	True ZDV Std Union	—	1/4-28 Flat Btm	N/A	N/A	N/A	Delrin	Natural
P-620	True ZDV Std Union	—	1/4-28 Flat Btm	N/A	N/A	N/A	PP	Natural
P-623	True ZDV Std Union	—	1/4-28 Flat Btm	N/A	N/A	N/A	ETFE	Natural
METRIC UNIONS
P-602	Metric Union	—	M6-Flat Btm	0.020" (0.50 mm)	0.41 µL	N/A	Delrin	Black
P-606	Metric Union, Female	—	M6-Flat Btm	0.060" (1.55 mm)	3.7 µL	N/A	Delrin	Black
P-622	Metric Union	—	M6-Flat Btm	0.020" (0.50 mm)	0.41 µL	N/A	ETFE	Blue
MALE UNION
P-645	Male Union	—	1/4-28 Flat Btm	0.062" (1.60 mm)	61.3 µL	500 PSI (34 bar)	PCTFE	Natural
BULKHEAD UNIONS
P-440	Union	—	10-32 Coned	0.020" (0.50 mm)	1.9 µL	1,000 PSI (69 bar)	PEEK	Natural
P-441	Union	—	1/4-28 Flat Btm	0.040" (1.00 mm)	2.9 µL	1,000 PSI (69 bar)	PEEK	Red
P-441N	Union	—	1/4-28 Flat Btm	0.040" (1.00 mm)	2.9 µL	1,000 PSI (69 bar)	PEEK	Natural
U-421	Union ZDV	—	10-32 Coned	0.050" (1.30 mm)	—	1,000 PSI (69 bar)	SS	—
LARGE BORE UNION
P-134	True ZDV Union	—	5/16-24 Flat Btm	N/A	N/A	1,000 PSI (69 bar)	PEEK	Natural
U-658	Union Assembly	1/4"	5/16 to 1/2-20 Flat Btm	0.188" (4.78 mm)	57 nL	1,000 PSI (69 bar)	PEEK	Black
ELBOW CONNECTORS
P-430	Elbow	1/16"	1/4-28 Flat Btm	0.020" (0.50 mm)	1.4 µL	1,000 PSI (69 bar)	PEEK	Natural
P-432	Elbow	1/8"	1/4-28 Flat Btm	0.062" (1.60 mm)	13.6 µL	1,000 PSI (69 bar)	PEEK	Natural

PART NO	DESCRIPTION	TUBING OD	THREADS	THRU-HOLE	SWEPT VOL.	PRESSURE RATING	MATERIAL

TEES & CROSSES
P-632	Tee	1/16"	1/4-28 Flat Btm	0.020" (0.50)	2.9 µL	1,000 PSI (69 bar)	ETFE
P-633	Tee	1/8"	1/4-28 Flat Btm	0.050" (1.25)	17.5 µL	500 PSI (34 bar)	ETFE
P-634	Cross	1/16"	1/4-28 Flat Btm	0.020" (0.50)	3.8 µL	1,000 PSI (69 bar)	ETFE
P-635	Cross	1/8"	1/4-28 Flat Btm	0.050" (1.25)	22.8 µL	500 PSI (34 bar)	ETFE
P-712	Tee	1/16"	1/4-28 Flat Btm	0.020" (0.50)	2.9 µL	1,000 PSI (69 bar)	PEEK
P-713	Tee	1/8"	1/4-28 Flat Btm	0.050" (1.25)	17.5 µL	500 PSI (34 bar)	PEEK
P-714	Tee	1/16"	1/4-28 Flat Btm	0.040" (1.00)	11.4 µL	1,000 PSI (69 bar)	PEEK
P-722	Cross	1/16"	1/4-28 Flat Btm	0.020" (0.50)	3.8 µL	1,000 PSI (69 bar)	PEEK
P-723	Cross	1/8"	1/4-28 Flat Btm	0.050" (1.25)	22.8 µL	500 PSI (34 bar)	PEEK
P-800	Tee	1/8"	1/4-28 Flat Btm	0.050" (1.25)	17.5 µL	500 PSI (34 bar)	PEEK
Y CONNECTORS
P-512	Y Connector	1/16"	1/4-28 Flat Btm	0.020" (0.50)	1.7 µL	1,000 PSI (69 bar)	PEEK
P-513	Y Connector	1/8"	1/4-28 Flat Btm	0.040" (1.00)	6.0 µL	500 PSI (34 bar)	PEEK
P-514	Y Connector	1/8"	1/4-28 Flat Btm	0.060" (1.50)	13.6 µL	500 PSI (34 bar)	PEEK
P-515	Y Connector	3/16"	5/16-24 Flat Btm	0.125" (3.20)	47.7 µL	500 PSI (34 bar)	PEEK
MANIFOLDS
P-150	7-Port Manifold	1/16"	1/4-28 Flat Btm	0.040" (1.00)	42.0 µL	1,000 PSI (69 bar)	PEEK
P-151	7-Port Manifold	1/8"	1/4-28 Flat Btm	0.062" (1.60)	83 µL	500 PSI (34 bar)	PEEK
P-152	6-Port Manifold	1/16"	1/4-28 Flat Btm	0.040" (1.00)	26.8 µL	1,000 PSI (69 bar)	PEEK
P-153	6-Port Manifold	1/8"	1/4-28 Flat Btm	0.062" (1.60)	62.3 µL	500 PSI (34 bar)	PEEK
P-154	5-Port Manifold	1/16"	1/4-28 Flat Btm	0.040" (1.00)	22.3 µL	1,000 PSI (69 bar)	PEEK
P-155	5-Port Manifold	1/8"	1/4-28 Flat Btm	0.062" (1.60)	53.8 µL	500 PSI (34 bar)	PEEK
P-170	7-Port Manifold	1/16"	10-32 Coned	0.020" (0.50)	2.2 µL	5,000 PSI (345 bar)	PEEK
P-190	9-Port Manifold	1/8"	1/4-28 Flat Btm	0.062" (1.60)	160 µL	500 PSI (34 bar)	PEEK
P-191	9-Port Manifold	1/16"	1/4-28 Flat Btm	0.040" (1.00)	139 µL	1,000 PSI (69 bar)	PEEK

PART NO	DESCRIPTION	TUBING OD	THREADS	THRU-HOLE	SWEPT VOL.	PRESSURE RATING	MATERIAL

STAINLESS STEEL ZDV UNIONS
U-411	Union	1/16"	10-32 Coned	0.007" (0.178 mm)	13 nL	20,000 PSI (1,380 bar)	SS
U-435	Union	1/16"	10-32 Coned	0.010" (0.25 mm)	20 nL	20,000 PSI (1,380 bar)	SS
U-402	Union	1/16"	10-32 Coned	0.020" (0.50 mm)	0.13 µL	20,000 PSI (1,380 bar)	SS
U-437	Union	1/16"	10-32 Coned	0.050" (1.25 mm)	0.84 nL	20,000 PSI (1,380 bar)	SS
U-438	Union	1/16"	10-32 Coned	0.067" (1.70 mm)	Near 0 µL	20,000 PSI (1,380 bar)	SS
UH-402	VHP Union	1/16"	10-32 Coned	0.010" (0.25 mm)	20 nL	30,000 PSI (2,070 bar)	SS
VICI (VALCO) COMPATIBLE STAINLESS STEEL ZDV UNION
U-322	Union	1/16"	10-32 Coned	0.020" (0.50 mm)	0.15 µL	20,000 PSI (1,380 bar)	SS
WATERS COMPATIBLE STAINLESS STEEL ZDV UNION
U-412	Union	1/16"	10-32 Coned	0.020" (0.50 mm)	0.10 µL	20,000 PSI (1,380 bar)	SS
PEEK ZDV UNIONS
P-704	Union	1/16"	10-32 Coned	0.020" (0.50 mm)	0.28 µL	5,000 PSI (344 bar)	PEEK
P-705	Union	1/16"	1/4-28 Coned	0.020" (0.50 mm)	0.21 µL	5,000 PSI (344 bar)	PEEK
P-706	Union	1/16"	1/4-28 Coned	0.050" (1.25 mm)	1.2 µL	5,000 PSI (344 bar)	PEEK
P-742	Union	1/16"	10-32 Coned	0.010" (0.25 mm)	0.07 µL	5,000 PSI (344 bar)	PEEK
P-760	Union	1/16"	10-32 Coned	0.050" (1.25 mm)	1.2 µL	5,000 PSI (344 bar)	PEEK
P-779	NanoTight™ Union Sleeve	1/16" Tubing	10-32 Coned	0.005" (0.125 mm)	8 nL	5,000 PSI (344 bar)	PEEK
COLUMN COUPLERS
U-287	Male Union	—	10-32 Coned	0.010" (0.25 mm)	3.6 µL	5,000 PSI (344 bar)	PEEK
U-284	Male Union	—	10-32 Coned	0.007" (0.178 mm)	1.3 µL	5,000 PSI (344 bar)	SS/Delrin

PART NO	DESCRIPTION	TUBING OD	THREADS	THRU-HOLE	SWEPT VOL.	PRESSURE RATING

VHP TEES & CROSSES
UH-427	VHP Tee, SST	1/16" OD	10-32 Coned	0.020" (0.50)	57 nL	30,000 PSI (2,070 bar)
UH-700	VHP MicroTee, PEEK/SST	1/32" OD	5/16-24 Coned	0.010" (0.25)	84 nL	15,000 PSI (1,034 bar)
UH-750	VHP MicroTee, PEEK/SST	360 µm	5/16-24 Coned	0.010" (0.25)	84 nL	15,000 PSI (1,034 bar)
UH-752	VHP MicroCross, PEEK/SST	360 µm	5/16-24 Coned	0.010" (0.25)	101 nL	15,000 PSI (1,034 bar)
STAINLESS STEEL TEES & CROSSES
U-428	Tee	1/16"	10-32 Coned	0.020" (0.50)	0.57 µL	20,000 PSI (1,380 bar)
U-429	Tee	1/16"	10-32 Coned	0.040" (1.00)	2.1 µL	20,000 PSI (1,380 bar)
U-430	Cross	1/16"	10-32 Coned	0.020" (0.50)	0.72 µL	20,000 PSI (1,380 bar)
U-431	Cross	1/16"	10-32 Coned	0.040" (1.00)	2.5 µL	20,000 PSI (1,380 bar)
PEEK TEES & CROSSES
P-715	Tee	1/16"	1/4-28 Coned	0.020" (0.50)	2.9 µL	5,000 PSI (345 bar)
P-716	Tee	1/16"	1/4-28 Coned	0.050" (1.25)	17.5 µL	5,000 PSI (345 bar)
P-726	Cross	1/16"	1/4-28 Coned	0.050" (1.25)	3.53 µL	3,500 PSI (241 bar)
P-727	Tee	1/16"	10-32 Coned	0.020" (0.50)	0.57 µL	3,500 PSI (241 bar)
P-728	Tee	1/16"	10-32 Coned	0.050" (1.25)	3.0 µL	3,500 PSI (241 bar)
P-729	Cross	1/16"	10-32 Coned	0.020" (0.50)	0.72 µL	3,500 PSI (241 bar)
P-730	Cross	1/16"	10-32 Coned	0.050" (1.25)	22.8 µL	3,500 PSI (241 bar)
P-170	7-Port Manifold	1/16"	10-32 Coned	0.020" (0.50)	2.2 µL	5,000 PSI (345 bar)
STAINLESS STEEL PRESSURE GAUGE TEE
U-433	Pressure Gauge Tee	1/16"	10-32 – 1/4 NPT	N/A	N/A	N/A

Key Definitions ▸

Frequently Asked Questions ▸

What are Idex Unions, Tees & Crosses used for?

Idex Unions, Tees & Crosses are used to connect, split, or combine fluid streams in chromatography, microfluidics, and general lab plumbing. They help create secure connections while maintaining consistent flow paths for reliable analytical performance.

When should I choose a Y connector instead of a tee?

Choose a Y connector when you want smoother flow splitting or merging with less turbulence than a tee. Reduced turbulence can help minimize solvent outgassing, improve baseline stability, and increase sensitivity in analytical results.

What is a zero dead volume (ZDV) connection and why does it matter?

A ZDV connection minimizes or eliminates internal void space where fluid can mix or pool. This helps reduce peak broadening, maintain sharper separations, and improve reproducibility in chromatography and other precision fluidic workflows.

How do I select the correct manifold size and tubing compatibility?

Start by choosing the number of ports needed (5, 7, or 9) based on how many streams you’re combining or splitting. Then select fittings matched to your tubing OD, such as 1/16” or 1/8”, and confirm the pressure rating required for your application.

What is the advantage of bulkhead unions?

Bulkhead unions let you route tubing through an instrument panel or enclosure while maintaining a secure connection. They are designed to mount through equipment housings, creating a clean interface between internal and external tubing runs.

What materials are commonly used for Idex unions and why?

Common materials include PEEK for broad chemical resistance and strength, and ETFE components for chemically resistant nuts and ferrules in low-pressure applications. Additional polymers may be used to provide cost-effective options depending on solvent compatibility and mechanical requirements.

How do I choose between standard unions, metric unions, and union assemblies?

Choose standard unions for typical low-pressure systems using common thread types, metric unions for metric-based setups, and union assemblies when you need specific materials or thread configurations such as 1/4-28, M6, or 10-32 flat-bottom threads.