Front and Rear O2 Sensors Replacement for Chevy 2012-2007 Colorado 2.9L 3.7L,2009-2007 Trailblazer 4.2L Upstream and Downstream Oxygen Sensors

Interchange Part Number: 234-4331 234-4294 Fitment: Compatible with Chevy 2012-2007 Colorado 2.9L 3.7L,2009-2007 Trailblazer 4.2L 4pcs O2 Sensors Product Specifications: Package Includes--2 x Oxygen Sensor Feature: The key parts including chip from top supplier; Quicker response times; 100% test before shipment; Stock parts direct replacement and with pre-coated threads to help installation; reduce harmful emissions, increase fuel economy, improve engine performance and prevent premature failure of the catalytic converter. Tip: Bank 1 Sensor 1=Upstream Right/Rear; Bank 2 Sensor 1=Upstream Left/Front; Bank 1 Sensor 2=Downstream Right/Rear; Bank 2 Sensor 2=Downstream Left/Front; sensor 1=Upstream, sensor 2=Downstream.