FIS stands for Fahrerinformationsystem, or Driver Information System. The FIS cluster has an LCD screen backlit by red LEDs in the middle of the cluster, which takes up the whole rectangular area where most VWs have the warning lights.
Full Fis clocks tended to come fitted with factory sat nav which would then mean you could get the directions into the middle screen.
Hold on I have some pics of them installed just find them
EDIT Sorry Rich I thought I had picks of them installed unfortunately they were of the half height ones.
As far as I'm aware they are fine,I fitted them and all worked OK and had 67k on the clocks.
Unfortunately I lacked the knowledge of coding the keys in,did the skc retrevial and changed mileage.
If I don't get a nibble on these in the next couple of days they will be coming off sale and I'm going to put them in my car and get them coded in properly.