The Zirconia sensor features a hollow ceramic cylinder made from Zirconia Dioxide. At the stoichiometric point the ECU will read a charge of approximately 0.45 volts while a rich fuel mixture will read 0.9 volts and a lean mixture will read 0.1 volts. The sensor is most sensitive near the stoichiometric point and less sensitive when either very lean or very rich. The ECU is able to read this change in voltage and modify the fuel injector output accordingly.