Compare Model Drawings, CAD & Specs Flange Size Flange Size 2 A1 B2 C3 Availability Price
In Stock
NW25 NW16 100 mm 27 mm 50 mm
In Stock
In Stock
NW40 NW16 130 mm 34 mm 65 mm
In Stock
In Stock
NW50 NW16 140 mm 40 mm 70 mm
In Stock
In Stock
NW50 NW40 160 mm 67 mm 80 mm
In Stock
In Stock
NW40 NW25 122 mm 61 mm 61 mm
In Stock

Please see reducing tee schematic for dimension callouts.


  • Component Type
    Reducing Tee Fitting
  • Series
    Series 31
  • Material
    304 Stainless Steel
  • Flange Type


ISO-KF Vacuum Flange Standard Dimensions

inch (mm)

The International Standards Organization has defined the interface dimensions of ISO-KF vacuum flanges allowing the interchanging of components that conform to the ISO-KF standard. The ISO-KF flange system provides is a modular building block method for creating a vacuum systems. Since component dimensions are standardized, elbows, tees, crosses or valves for a given flange size can be interchanged. The flanges are sexless and the seal is symmetrical allowing components to be rotated. By using ISO-KF standard components, vacuum system assembly is quick and cost effective.

Joining ISO-KF Vacuum Flanges

ISO-KF vacuum flange components are joined by inserting a centering ring seal between the two flange faces, then securing the assembly with a flange encompassing clamp. There are a variety of flange clamp choices available. The wing-nut flange clamp is hand tightened until metal contact is felt. The toggle flange clamp is convenient and easy to use and provides enough sealing force to fully compress the O-Ring, so that the flanges and the centering ring are metal to metal. The self-adjusting clamp locks in a positive method making it ideal when clamp must be removed frequently, like leak testing or gauge calibration. Bulkhead flange clamps attach an ISO-KF flange directly to a chamber or base plate. The two-part, bolted clamp fits over the flange with a centering ring assembly used between the flange and the opening.