Temperature controlled fan speed freely adjustable: you can adjust the fan speed with the "OK" button and the "+" and "-" buttons. You can also turn the fan on and off by setting a certain temperature and increase or decrease the fan speed depending on the temperature. Make your fan smarter. LCD display temperature and speed: This temperature-controlled fan speed controller has a digital display that provides real-time information about the speed and temperature of the fan, so you can adjust the fan speed and temperature settings at any time. Wide range of applications: this controller controls the fan speed via the 4-wire standard PWM signal. The signal specification is 25 kHz, 5 V. It supports conventional PC cases, CPU and many server 4-wire fans (note that the 2 and 3 wire fan speed control is not possible). Important parameters: Supply voltage: DC 12V; voltage range: DC 8~12V (operating voltage of the circuit, please note the fan voltage range); Fan current: 3.5A; PWM range:1~1000.5% (signal percentage does not correspond to actual speed);PWM frequency: 25kHz (1kHz); temperature. measuring range: -9.9~99.9C; Temperature measurement error:1.2~1.9C Color: As Shown Material: plastic Package Contents: 1*Controller 1*Probe Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.