That may well be the case. I am curious as to why that sensor is called out specifically as an air/fuel sensor as opposed to an O2 sensor, why the output is 0-5 V as opposed to the 0-1 V of a normal O2 sensor, why it has 4 wires instead of 5 or more for wide band sensors, and why it costs $200 or more depending on who is selling it. Of course, you doesn't always get what you pay for.