For simultaneous connection of 4 fans with 3-pin Molex connector (CPU coolers, case fans, etc.) directly to the power supply. With this special cable to two fans can run at 5 volts, instead of 12 volts. The reduction leads to a quieter noise, thus helping to reduce the overall volume of the enclosure. The other two fans run regularly on 12 volts. Please note that due to the reduced rotational speed of a fan and therefore the air flow is lower.