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The Straub Open-Flex Coupling comes in several different wrap-around configurations that allow them to be used to connect or repair pipework without removing existing pipes. Choose from jointed, slotted, two-part, or three-part.

A progressive sealing effect increases the force on the sealing lips as the pressure in the pipe increases. This gives the pipework flexibility at every joint with anchoring and sealing functions that are independent from each other.

You can use these reusable Open-Flex Coupling on plain-ended pipes without additional modifications.

The Open-Flex 1L model has a size range of 48.3–168.3mm while Open-Flex 2 is available from 172–2032mm.

Technical specifications




Open-Flex 1L
Open-Flex 2

Size range

Open-Flex 1L: 48.3–168.3mm
Open-Flex 2: 172–2032mm

Nominal pressure

Open-Flex 1L: 16 bar
Open-Flex 2: PN2.5, PN6, PN10, PN16, PN20, PN25

Material specifications


Open-Flex 1L: AISI 316 L or similar
Open-Flex 2: S355MC hot-dip galvanised, AISI 316 L or similar


AISI 4135


AISI 12L14, galvanised
AISI 316 L or similar

Strip insert

Open-Flex 1L: AISI 316 L or similar/VDF, PVDF
Open-Flex 2: AISI 316 L or similar/HDPE

Sealing sleeve and temperature range

EPDM (-20°C to 100°C)
NBR (-20°C to 80°C)
FPM/FKM (-20°C to 180°C)

How we help you select your SPI package:

1. Tell us what you need

Tell us about your project. What items are on your MTO list, and what options do you need to weigh up?

2. Choose the right solution

Weigh up the options. We'll do the analysis, discuss the options with you, and recommend the right products—the choices we'd make in your shoes.

3. Get the job done

You get the complete package delivered to site as ordered. The right price, reliable delivery, and everything to spec. No surprises.

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