Zalman ZM-MFC2 Multi Fan Controller Review
 

There are times I’d like to be able to turn the fans up to the max for short periods of time, like when overclocking. And to be honest, there are times I miss the look of those analog knobs on the front of my rig. Call me old skool, call me old man, I’m sorry, I like dials and knobs.

http://www.ocia.net/reviews/mfc2/page1.shtml