4pcs For Mazda For CX-9 2007 2008 2009 2010 O2 Upstream Downstream Lambda Oxygen Sensor O2 Sensor

4pcs for Mazda for CX-9 2007 2008 2009 2010 O2 Upstream Downstream Lambda Oxygen Sensor. Replaaces OEM Part Number:234-4372 234-4610. Fit for:For 2007 2008 2009 2010 for Mazda for CX-9 3.7L. "Oxygen sensors solve jitter, fault lights, exhaust emissions, optimize exhaust and fuel economy, practical and energy-saving. monitor the oxygen content in the engine combustion chamber in real time, so as to adjust the fuel injection, improve fuel economy, reduce fuel consumption and emissions."