Reducing Unions


UHPLC reducing union

Stainless steel UHPLC reducing union Back to main content

UHPLC bulkhead reducing union

Stainless steel UHPLC bulkhead reducing union Back to main content
stainless reducing union

Internal reducing unions connect two sizes of tubing, using zero dead volume internal fittings on each end. In the bulkhead version, the bulkhead nut is on the side with smaller tubing. Standard material is 300 series stainless. Also available in Hastelloy C, gold-plated stainless, and titanium versions.

Select the union with the bore that matches the ID of the tubing. If the IDs are different, choose the union with a bore which matches the smaller tube bore.

stainless bulkhead reducing union

Bulkhead versions are designed to be mounted through an instrument panel or on a bracket. The fitting body is undercut so that it bites into the panel when the mounting nut is tightened, eliminating the need for a lock washer.

Standard Reducing Unions

Tubing OD Bore Product No.
1/16" to 1/32" 0.15 mm ZRU1.5XC
0.25 mm ZRU1.5
0.50 mm ZRU1.5L
1/32" ZRU1.5T
1/8" to 1/32" 0.25 mm ZRU2.5
0.50 mm ZRU2.5L
1/32" ZRU2.5T
1/8" to 1/16" 0.25 mm ZRU21C
0.75 mm ZRU21
1/16" ZRU21T

Bulkhead Reducing Unions

The "Hole" heading in the table below refers to the size of the hole required for mounting the union through a bulkhead or panel.

Tubing OD Bore Hole Product No.
1/16" to 1/32" 0.25 mm 5/16" ZBRU1.5
0.50 mm 5/16" ZBRU1.5L
1/32" 5/16" ZBRU1.5T
1/8" to 1/32" 0.25 mm 5/16" ZBRU2.5
0.50 mm 5/16" ZBRU2.5L
1/32" 5/16" ZBRU2.5T
1/8" to 1/16" 0.25 mm 5/16" ZBRU21C
0.75 mm 5/16" ZBRU21
1/16" 5/16" ZBRU21T



With a bulkhead union, an O-ring can be installed between the body and the panel to allow operation in purged environments.