Bosch 13077 Oxygen Sensor, Original Equipment (Buick, Chevrolet, GMC, Oldsmobile, Pontiac) Protection tube ensures 100% accurate sensor performance Double laser-welded stainless steel body is totally submersible to seal tight and protect against contamination for long life Fast-acting heater optimizes sensor operation (on3- and 4- wire sensors only) Coated threads for easy installation