The higherbro 4x 4 Air Fuel Ratio Oxygen O2 Sensor is designed for BMW 328xi models from 2007-2008 with a 3.0L engine and BMW 328i xDrive models from 2009-2013 with a 3.0L engine. This package includes 4 sensors in total, with 2 upstream and 2 downstream sensors. The sensors are made of aluminum oxide and have an upper temperature rating of 800 degrees Fahrenheit. They are modern in style and specifically designed for use as oxygen sensors. Each sensor is backed by a one-year quality guarantee. Before purchasing, please verify that your vehicle is compatible by checking the 'Select Your Vehicle' option at the top of the page, taking note of the make, model, year, engine, and any additional notes.