Including: 2x Upstream + 2x Downstream Fit BMW 325CI 2001-2002 2.5L; Fit BMW 325I 2001-2002 2.5L; Fit BMW 330CI 2001-2002 3.0L; Fit BMW 330I 2001-2002 3.0L; Fit BMW 525I 2001-2002 2.5L; Fit BMW 530I 2001-2002 3.0L; Fit BMW Z3 2001-2002 2.5L 3.0L; Fit BMW X5 2001-2005 325XI 2.5L; Fit BMW 330XI 2001-2005 3.0L; Fit BMW X5 2001-2006 3.0L; Fit BMW Z4 2003-2005 2.5L 3.0L; Fit BMW X3 2004-2005 2.5L 3.0L; Fit BMW 323CI 2000 2.5L; Fit BMW 328CI 2000 2.5L; Firm package with air Bubble bag One Year Quality Guarantee Before buying, check the “Select Your Vehicle” check (Make, model, year, engine, Note,The engine and Note in particular) at the top of the link to see if your car can be used. Upgrade your vehicle's emission monitoring with our robust Guniang Set of 4 Oxygen O2 Sensors, meticulously designed for a wide range of BMW models from 2001 to 2005. Crafted with high-quality materials like Stainless Steel, Ceramic, and Platinum, these sensors ensure durability and precision. Each set includes 2 Upstream and 2 Downstream sensors, offering comprehensive coverage for your vehicle's needs. With a measuring range of 0 - 25% O2 and an upper temperature rating of 80C, these sensors are built to withstand the rigors of the road. They are compact, measuring 11cm in width, 15cm in length, and 11cm in height, making them easy to install. Backed by a one-year quality guarantee, you can trust in their performance. Before purchasing, ensure compatibility with your specific vehicle model and engine using the 'Select Your Vehicle' tool.