1、PWM Speed Controller: This PWM fan speed controller adopts PWM control technology to realize temperature control and speed regulation. The fan speed can be controlled according to the tested temperature. The higher the temperature, the faster the speed, the lower the temperature, the slower the speed 2、Auto Stop: This PC fan speed controller controls the fan to stop running when the ambient temperature is lower than the set starting temperature. 3、Adjustable Mode: This PWM fan temperature controller supports start up temperature adjustment(10℃ to 50℃), turn the switch to the A position and to switch to the adjustable mode. 4、Fixed Mode: Flip the switch of this PC fan speed governor to the F position to switch to the fixed temperature mode(30℃), which won't be affected by potentiometer. 5、19.7in Cable: This PWM fan speed governor is designed with approximately 50cm/19.7in cable which can be easily connected to your computer chassis. 1 x PWM Fan Speed Controller Item Type: PWM Fan Speed ControllerMaterial: Printed Circuit BoardSupport: All Kinds of 12V/24V 2/3/4 Wire Fan/MotorMaximum Driving Current: 4ASupported Mode: Temperature Adjustable Mode/Temperature Fixed ModeCable Length: Approx. 50cm / 19.7in ( Manual Measurement, Slight Error May Exist )