Example Cross Section - CAT6 FTP PE BLK
SFX Cat6 F/UTP
4 Pair, 23 AWG solid bare copper wires twisted, SPE Insulation. Crossmember/pair separator, overall PVC, LSZH or PE outer jacket.
Screened versions are used where proximity to RF equiptment may produce electromagnetic interference. It is also used as a security measure should eavesdropping be apparent.
There are various screening options available dependant on enviroment and application.
The most common is FTP (Foil Twisted Pairs) which is available from stock.