Product description 1.With signal output indicator light. 2.Size: 32mm X22mm X30mm length * width * height; 3.The main chip: LM393, MQ-x gas sensing probe; 4.Working voltage: DC 5V; 5.With signal output indicator light; 6.The dual signal output (analog output and TTL output); 7.The analog output and increased with the increase of concentration, the higher the concentration higher voltage; 8.Has a very high sensitivity to sulfide, benzene vapor, smoke and other harmful gases; 9.With a long service life and reliable stability; 10.Quick response and recovery characteristics; 11.With mounting holes, easy mounting; 12.The probe can be plug design, convenient test Application: For harmful gas family, environment detection device, is suitable for the detection of the ammonia, aromatic compounds, sulfide, benzene vapor, smoke and other harmful gas, gas sensitive element concentration range: 10 to 1000ppm provides reference cases. Package Included: 1pcs MQ-2/MQ-3/MQ-4/MQ-5/MQ-6/MQ-7/MQ-8/MQ-9/MQ-135