4Pcs Up & Downstream Oxygen Sensors Fit 2018-2020 Ford F-150 Lariatc XL XLT 2.7L Fit for: 2018-2020 Ford F-150 Lariatc XL XLT 2.7L Specifications: OE Numbers: 234-5173, 234-5174, 234-8050 Product Material: Stainless Steel Product Color: Silver Installation Position: Upstream, Downstream Functions: 1. The Upstream oxygen sensor is used to Monitor Raw Exhaust Gas to Adjust Air-fuel Ratio in Real-time, i.e., it is used to Detect Whether the Exhaust Gas Exceeds the Standard. 2. The Downstream oxygen sensor is mainly used to Detect Whether the Three-way Catalytic Converter Works Normally. Packaging Weight: 527 g .
