Since a few years there is a new one.
FA = Feldwebel-Anwaerter.
It was introduced to make the NCO´s carrier more interesting for young soldiers.
You will be Feldwebel after three years service.
UA was a longer way.
First you was UA, than Gefreiter UA , maybe Obergefreiter or HG UA, than UA mbL (mit bestandenem Lehrgang, completed succesful NCO´s school) than Unteroffizier and Stabsunteroffizier.
This took 3-5 years.
After that, if you had good certifications you were send to the Feldwebel-Lehrgang, after compelting it succesful you were waiting to be promoted to feldwebel.
I know a guy who was 4 years Stabsunteroffizier, because there was no possible position for him to get Feldwebel. He left Bundeswehr after 8 years aas Stabsunteroffizier whit the paygrade of a Feldwebel, but without the chrevron.
Now the FA insures you that you will be Feldwebel after three years.
The equivalent to the Navy is BA, Bootsmann-Anwaerter.
The FA shows a golden cord, smiliar the silver one for OA.
The BA shows a second UA chevron.
http://de.wikipedia.org/wiki/Feldwebelanw%C3%A4rter