A multi gas sensor detects a specific gas and measures whether the gas is present near the sensor, or its content in the air. Therefore, gas sensors are often indispensable in safety systems. The gas sensor has many different types and can measure different gases. There are sensors that measure non-toxic gases such as oxygen and carbon dioxide, and sensors that detect toxic gases such as carbon monoxide, TVOC, and ammonia. Multi Gas sensors are often used in flammable, explosive and toxic places to protect workers.