There is standard value for the deceleration speed. The marked deceleration value is an approximate for reference. Through the step-down line, the starting of the fan is reduced, thereby reducing the speed of the fan and achieving the effect of mute; Features 3 Pin Male to Female Connector. Easy installation. Long service for time. Designed with a resistor on the cable. Quite practical and useful. Use the 3-pin cable to the power supply to your cooling fan, it will reduce the speed of the fan and output dramatically.