Features: This device is a 4 wire temperature controlled fan speed regulator that allows for automatic or manual adjustment of fan speed bases on temperature readings. It features a digital display showing both current temperature and the fan’s rotational speed in RPM (revolutions per minutes). Systems help maintain great cooling performances and energy efficiency by increasing fan speed as temperatures rise and reducing speed when cooling demand is lower. Support low temperature shutdown of fan within 3A (directly turn off the fan power), supporting reverse timing fan, and support display of fan speed at 10000 rpm. Note: This controller only control the fan speed adjustment controlled by a four wire standard PWM signal, with a signal specification of 25KHz 5V. Specifications: Component: Plastic Size: about 6x2.9x2.1cm/2.36x1.14x0.83inch Working voltages: DC8-16V Fan current: no more than 3.5A PWM ranges: 1-1000.5% PWM frequency: 25KHZ (1KHZ) PWM signal amplitudes: 5V (no load) Temperature measurement ranges: -9.9-99.9° Temperature measurement error: The error is Belows 1.2°C in the ranges of 0-50°C, and Other ranges is less than 2℃ Package Includes: 2pcs Fan Temperature Controller note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to difference between different monitors, the picture may not reflect the actual color.