The product is a NEW DENSO 234-4257 Oxygen Sensor designed for 08-12 Chevy Express, GMC 3500, and 4500 Savana vehicles. As indicated by the Manufacturer Part Number, this sensor is manufactured by DENSO, a reputable brand known for producing high-quality automotive parts. The Oxygen Sensor, also known as O2 sensor, plays a crucial role in monitoring and regulating the oxygen levels in the vehicle's exhaust system to ensure optimal engine performance and emission control. This specific sensor is tailored for compatibility with the mentioned vehicle models, making it a reliable choice for replacement or maintenance needs.