This Swagelok® Ultra-Torr® vacuum fitting reducing union connects a 3/8" to a 1/4" OD tube

Swagelok Ultra-Torr fittings are designed for vacuum system use only and offer reliable vacuum sealing performance up to ultra-high vacuum, even after repeated connects and disconnects.

Ultra-Torr fittings are constructed of 316 stainless steel and use a knurled nut for easy, finger-tight assembly. No tools are required to assemble or disassemble the fittings.

Unlike standard Swagelok compression fittings (used for both vacuum and pressure applications), Ultra-Torr fittings do not use a permanently swaged ferrule on the end of a tube. Instead, the seal is made by compressing an O-ring on the tube end. Because a ferrule is not used, these fittings can repeatedly seal glass, metal or plastic tubing without permanent alteration to the tubing.

Ultra-Torr fittings employ standard fluorocarbon FKM O-rings which are rated for -25 to 400°F (-31 to 204°C). The fitting design has been helium leak tested to a maximum rate of 4x10-9 std cc/sec at ambient temperature. The leak rate increases as temperature increases due to permeation through the O-ring.

Ultra-Torr fittings are available in standard fractional outside tubing diameters from 1/16 to 1-1/2 inches. A variety of connectors, unions, tees and elbows are available to fulfill virtually any vacuum system tubing connectivity requirement. High purity materials virtually eliminate these fittings as a source of system contamination.

Download the catalog of Swagelok Ultra-Torr fittings here.

Fitting specifications are shown in the second image.