350W Power supply, ideal for powering RepRap 3D Printers, CNC Machines and other electronics. Available in 12V and 24V versions. 350W is more than enough power for a RepRap 3D Printer, including 5 Motors, Extruder, Heated bed and More. Manufactured to a very high quality from a reputable supplier. The fan is always on, but varies it’s rpm according to temperature.