Controlling 3-pin fans via a PWM signal was an insoluble problem until now. Phobya has taken on this problem and presents with the 4-pin PWM to 3-pin converter an elegant and easy to use solution. With the 4-Pin PWM to 3-Pin transformer all 3-Pin fans can now be controlled via a normal PWM signal. To do this, connect the converter to your mainboard or your PWM fan controller while you connect the fan to the converter. Now your 3-pin fan can be controlled like any other PWM fan. The converter recognises the PWM signal and controls the 3-pin fan with an appropriate voltage. This way you can control your fans easily and simply. The converter is able to supply an output voltage of 1A, which corresponds to 12W. This means that you can use a Y-splitter to control several fans simultaneously via the converter. Technical Details: Dimensions (LxWxH): 50 x 39 x 18mm Connector: 1x 4 Pin / 1x 3 Pin Power connector: 4 Pin Connector Mounting: Double sided adhesive tape for mounting on/in the case 4 Pin PWM to 4 Pin PWM Cable: black sleeved 50cm  Included in delivery:  Phobya 4Pin PWM to 3Pin Transformer Single .