This product is used to detect smoke and combustible gases, including hydrogen, methane and propane (LPG) gases. Features: Used to detect fumes and combustible gases, including hydrogen, methane and propane (LPG) gases. Double output signal. Analog level output (AO pin) and TTL (DO pin). The TTL output signal is normally low and becomes high when gases are detected. The threshold is adjusted by the built-in potentiometer. Analog output voltage 0 ~ 5V. The higher the concentration of gas or smoke, the higher the voltage. Has good sensitivity for liquefied gases, natural gases, urban gases and smoke. Has four screw holes for fixing. Has fast response, long service life and reliable stability. Suitable for domestic and industrial use. Features: Input voltage: DC 5V Power dissipation (current): 150mA Item size: 32 * 22 * 20mm / 1.26 * 0.87 * 0.79in Package size: 45 * 45 * 20mm / 1.77 * 1.77 * 0.79in Package Weight: 13g / 0.46 ounces Note: 1. Due to different display screens and lighting effects, the actual color of the item may be slightly different from the color shown in the photos. 2.Please allow a little measuring deviation. to manual measurement.