Evercool Twister Fan Speed Controller - PCI Slot or 3.5" Bay Mount - Adjustable Cooling for PC Case, Gaming Rig & Workstation - Perfect for Overclocking & Silent Operation

Simple to install. Works precisely as intended and described for a common case fan. I have an older case, so experienced none of the installation issues mentioned by others with tool-less cases. I can now tune the noisy fan in the front of the case so that it is barely audible now, but still provides adequate airflow. The rear fan in my power supply automatically adjusts speed based on internal temperature and is much quieter because my power supply is relatively new.I also really appreciated that this speed control comes with both a rear expansion slot plate, or a front 3.5" plate. Not having a spare 3.5 front slot, I bought it with StarTech 3.5-Inch to 5.25-Inch Floppy Mounting Kit Bracket and it matches (black) and fits perfectly in a spare 5.25 front slot.