The Yellow Jacket 69373 is a handheld combustible gas detector with a state-of-the-art sensor utilizing the latest technology to achieve superior sensitivity with instantaneous response time. The 69373 gas detector uses advanced electronic circuitry to detect all hydrocarbon and other combustible gases including propane, methane (natural gas), butane, acetylene, isobutane, and benzene. The Yellow Jacket 69373 is designed to make leak detection fast and reliable in a wide range of applications including residential and commercial combustion appliances, gas lines and pipes, heat exchangers, marine bilges, and numerous other applications.