27 PC for Case Fan Speed Reduction Silent Connector Resistor Cable Quiet Mo R7UB Pins:3/4 pin OOTDTY There a two types o connectors or sale: 3 pin and 4 pin connector. 3 pin connector is dedicated for regular 3 pin for case fans 4 pin connector is dedicated for PWM controlled fans which can work with a variable speed. This simple connector let your PC for case fan to run in silent Built-in resistor, reduce fan's speed about 35%, so your for case will be more quiet and more comfortable for your ears. Length:11.3cm/4.45inch 11.5cm/4.53inch Note: Please allow 1-3mm error due to manual measurement. pls make sure you do not mind before you bid Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package Includes: 1x fan silent connector