Graphite

Graphite is the best material to work at high temperature and at the same time is the softest ferrule. Therefore it fits the capillary column and seals effectively at only ¼ turn past fingertight. As this is a very soft material, thery are easily destroyed or deformed. Ideal for FID and NPD detectors. Do not use with MS or other oxygen sensitive detectors. 
Upper temperature limit 450ºC.

Vespel/Graphite

Vespel /Graphite ferrules are recommended for applications with GC/MS interface or other oxygen sensitive detectors. 
The ferrule composition is 60% polymide and 40% graphite. It is a ferrule for general use in Gas Chromatography. 
It is mechanically robust and forms a perfect seal. It is a reusable ferrule. It needs a frequent retightening. Limit temperature 400ºC
85% Polymide (vespel) 15% graphite for Agilent ferrules.

Vespel

The composition of the Vespel ferrule is 100% polyimide. 
It is mechanically robust. It can be removed and reused several times. It is an ideal material for glass and metal columns. 
It needs a frequent retightening. Limit temperature 350ºC.

Short ferrules for Agilent 4890, 5890, 6890 except for GC/MS

Standard ferrules

Ferrules with two holes

Reducing ferrules

Special ferrules for shimadzu