DINUY CO2 Sensors detect CO2 concentration levels in a room and act to establish the correct level. Our sensors allow the ventilation and air renewal systems of the room to be connected automatically. The three colors of the sensor mark the CO2 concentrations: low level (green), yellow (intermediate) and red (high). DINUY sensors incorporate a sound warning with different levels (yellow level with 1 beep every 5 minutes and red level with 2 beeps every 5 minutes).