Description:Cat Hall effect fan speed sensors have Hall elements. Active Hall effect sensors require an external electrical power supply. Waveform is function of the target gear square wave output. Frequency is proportional to the magnet target as it passes the sensor, but the voltage level is not (unlike passive speed sensors).Attributes:• Bolt-n-Go installation• Work together with magnets• Low accuracy since one signal per resolutionApplications:• Fans• Cat fan speed sensors are application specific sensors. Consult your owner’s manual or contact your local Cat Dealer for more information.