IDEX flat-bottom fittings

Wide range for fast and reliable connections

The comprehensive range of IDEX flat-bottom fittings are designed to eliminate any tubing flanging, thereby enabling faster and more reliable connections of polymeric tubing. To suit a wide range of assembly requirements, the IDEX flat-bottom fittings are available in a variety of designs, providing different pressure tolerance and handling features. Some fittings are available for several different port designs and many tubing dimensions, whereas some of the more specialized fittings only fits the most popular flat-bottom port designs (1/4-28 & M6x1) and the more common tubing outer diameters (1/16″ & 1/8″). Two of the more widespread fitting systems for flat-bottom ports include the Flangeless™ and Super Flangeless™ designs, although the newer Intuitive™ torque-limiting and One-Piece Super Flangeless™ systems are gaining popularity for several assemblies.

Biotech Fluidics maintains a considerable stock of many frequently requested fittings and connectors for speedy delivery. We are also happy to provide guidance to the most suitable solution for a particular flow path assembly situation. Please contact us for further discussions about your application.

Port geometries

6-40 flat-bottom
6-32 flat-bottom
10-32 flat-bottom
1/4-28 flat-bottom
M6x1 flat-bottom
5/16-24 flat-bottom
1/2-20 flat-bottom

Popular choices

Flat bottom port fitting systems

Super Flangeless™ fittings

Get unmatched sealing performance and pressure tolerance for flat-bottom ports. The sturdy design of Super Flangeless™ fittings seals efficiently even through vibrations and allows tightening of the nut without twisting the tubing. Available for many different port thread geometries and tubing dimensions ranging from 1/32″ (0.8 mm) to 3/16″ (4.8 mm).

Flangeless™ fittings

The original Flangeless™ fittings are a cost-effective alternative due to their few components and quick replacement. This flat-bottom fitting system offers one of the most comprehensive product ranges of nuts for many port designs and ferrules for numerous polymer tubing outer diameters from 1.0 mm (with sleeve) up to 5/16” (7.9 mm).

One-Piece Super Flangeless™ fittings

The One-Piece Super Flangeless™ fittings are extremely easy to use thanks to an innovative design that join the ferrule to the nut, while still providing the ability for the two to rotate independently during assembly. This type of fully inert high-performance fitting is available for polymeric tubing outer diameters of 1/16” & 1/8” connected into 1/4-28 & M6x1 flat-bottom ports.

Intuitive™ torque-limiting fitting

This clever design provides a haptic click feedback when the right amount of torque has been applied to secure a leak free connection. The Intuitive™ fitting is designed for 1/4-28 UNF ports and fits several different IDEX connection systems, including Super Flangeless™, Flangeless™, and traditional flanged tubing, both for 1/16” and 1/8” OD tubing.

BioTight™ fittings

The new IDEX BioTight™ fitting system provides consistent biocompatible performance in low-pressure assemblies up to 200 psi (14 bar) in 1/4-28 flat-bottom ports. These fittings are ideal for small spaces and require very little torque thanks to the metal-free press-fit ferrules that are available for 1/16” & 1/8” tubing OD.

VacuTight™ fittings

Ideal for airtight, dependable connections, under vacuum and low-pressure conditions. The ingenious VacuTight™ flat-bottom ferrules prevents over-compression and tubing ID reduction. Currently available for 1/4-28 & 10-32 flat-bottom port designs with 1/16″ & 1/8″ tubing OD.

Metric threaded fittings

A practical summary of metric threaded nuts from different fittings systems. Explore the options that the Flangeless™, Super Flangeless™, One-Piece Super Flangeless™, and Intuitive™ torque-limiting fittings give you for metric threaded M6x1 flat-bottom ports.

Large bore fittings

A convenient collection of nuts and ferrules for large bore tubing, including 4.0 mm, 3/16”, 1/4″, and 5/16” outer diameter. Contains options from the Flangeless™ and Super Flangeless™ fitting families, plus some related barbed connectors.


Consult the Periodic Table of Analytical Fittings for a quick overview, the Fittings 101 for guidance and learning, and the IDEX Catalogue for product details, or contact Biotech Fluidics for expert advice.

Periodic table of
analytical fittings

Fittings 101
guide booklet

Complete IDEX

Any questions?

If you have any inquiries about our products and services, we’re here to help.

Phone: +46 300 56 91 80