The NF-A4x10 5V PWM is a special PWM-controllable 5-V version of Noctua's highly optimised silent 40x10-mm premium fan that uses the AAO frame system and advanced aerodynamic design measures such as Flow Acceleration Channels. The specially designed NE-FD3 PWM IC with integrated Smooth Commutation Drive technology and the SSO2 industry standard bearing guarantee excellent smoothness and superb long-term stability. Note The NF-A4x10 5V PWM is a 5-V fan and cannot be operated with 12 V. Operation using common 12-V power sources such as fan connections for PC motherboards will damage the fan. 5-V version with PWM 40 mm PWM-controlled fans with 5 V are often used in network and storage devices in particular. With the same operating voltage, PWM support and the included OmniJoin adapter set, which allows proprietary connectors to be connected, the NF-A4x10 5V PWM is ideal for replacing noisy or defective 5-V 40-mm fans with PWM.