Features: There are five types, single gas alarm detection/ solenoid for valve/single pipe shutoff for valve/alarm detection+solenoid for valve/ alarm detection+ pipe shutoff for valve, selecting according to your needs. Work as standalone : detect the gas leakage ,the detector will sound alarm and the indicator light will flash . Work with solenoid for valve : detect the gas leakage ,the solenoid for valve will shut off automatically . Work with pipe cutoff valve: detect the gas leakage, the pipe will cutoff automatically. Locates combustible & explosive gas leaks from methane / natural gas, propane, fuel, ethane, butane, alcohol, coal gas, gasoline, toluene, kerosene, sewer gas, and other flammable gases. Suitable for household & commerical use. Specifications: Material: ABS+ Aluminum Size 1: 105x90x55mm/ 4.13x3.54x2.16 in Size 2: 90x65mm/ 3.54x2.55 in Size 3: 105x73mm/ 4.13x2.87 in Package Includes: 1x Gas Alarm Detection note: Please allow 1-3cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item.