4pcs Upstream and Downstream Oxygen Sensor 234-4668 Sensor 1 and Sensor 2 Replacement for 2003-2005 Chevrolet Silverado 1500, 2003-2005 Chevrolet Tahoe, 2005 GMC Sierra 1500/Yukon PART NUMBERS: 234-4668 x4 Compatible with: 15284, 21546, SG1857 2 Front upstream and 2 rear downstream oxygen sensors This is Brand New & High Quality Aftermarket Product service with Laser weld and Viton sealing system. Meet the professtional specification as OEM parts, for stable performance & durable Please check the description or use the year/make/model drop down bar and interchangeable part numbers to confirm the compatibility before purchase