⚠️ The following 2 models for gas natural gas gas gas liquefied gas and other gas leakage alarm ⚠️ (210 alarm) concentration temperature display voice mobile phone alarm APP monitoring send 2 meters power cord (209 gas alarm) voice alarm fault self-test send 2 meters power cord (218 alarm) voice mobile phone alarm APP monitorING USB power supply (send 2 meters line) ⚠️ The following 1 model for charcoal gas Liquefied gas and other carbon monoxide alarm ⚠️ (002 carbon monoxide alarm) sound and light alarm + concentration display + Low power consumption comes with a 9V carbon battery