CHIEFTEC 120x120x25mm Ball Bearing PWM F

Variable-speed fan controllers for computers usually use PWM (pulse-width modulation), as it is far more efficient when compared to the traditional one. The PWM technology allows the 4-pin fan Chieftec AF-1225PWM to be more temperature-sensitive, so that the turning-speed can be adjusted automatically over the BIOS setup if your mainboard supports this specification.