NZXT Sentry LXE External Fan Controller @ BCCHardware
Quote: "Using the NZXT Sentry LXE is very straight forward. You have the option to set each fan in manual mode or set it to auto. The touch screen makes it a breeze. When in manual mode, just touch the screen on the desired fan and then adjust it with the plus or minus symbol to your desired speed. Auto is the setting that I prefer as it automatically adjusts fan speed according to temperature at each probe."
Read the review here