Bought an Oxygen Sensor that turned out to be a cheap knockoff for the 21512 NTK/NGK brand. The box was similar, but said NK on it. It only lasted 6 months. When I contacted the company for the warranty replacement, their contact info was bogus. Should have checked them out a little better. This time I did more research when I found this product. Once I verified it was legit, I ordered it. It was the cheapest price I could find for this specific brand. Haven't had any problems so far, but it's only been a month since I installed it. But it is an NGK/NTK brand and they are high quality products.