NZXT Fans?

[HUNTER.P]

Just looking at these and unsure what all the letters mean?

Ref. http://www.nzxt.com/new/product.php?series=14

We have FN...RB, FS...RB, then FX...LB fans?

What are the pros and cons of each? And does anyone happen to know what ones are included in the Phantom Case?

 

[Helios1234]

FN seems to be their 1309RPM fans whereas FS is their 'Silent' range. FX for extreme performance so higher RPM than the others. RB means rifle bearing.