HDE 3.5" Bay Four Channel Turn Knob Multi-Fan Cooling Controller Panel Control fan speeds for four fans | Cool down desktop computer to enhance airflow Optimal cooling performance is obtained by connecting the computer fan to Fan 1 Housing case fits into 3.5 inch bay | Fits 5.25 inch bay with mounting rails and a filler panel Voltage of fans is between 6V-12V Blue LED lighting is ultra bright and provides style to your desktop