The working principle primarily utilizes the electrical conductivity of zirconia to measure the oxygen concentration in gases. Marathon models typically start with "F" or "MMI", offering a complete range, with high-temperature resistance but fragile nature. Available lengths include 600, 800, 1000, 1200, and 2000, with a diameter specification of 25mm. Jinan is known as "Quan Cheng (Spring City)" and is located on the coast in eastern China.nomic big province-Shandong the provincial capital of the province.Jinan is a whole province politics, economy, culture, science and technology, education and banking center.Jinan is also a national approval of the coast open city and vice- province class city.