Diffrence between AFR Sensor and O2 Sensor?

[barry_mann]

I was looking at a parts diagram of my sensors and noticed that what i thought was a O2 sensor on my exhaust manifold is truly called a Air Fuel Ratio Sensor. They call the 2 other sensors on the exhaust O2 sensors. What is the diffrence? The look physically the same.

2008 Nissan Altima

[adidas2go]

AFR Sensor, O2 Sensor, Oxygen Sensor. They're all the same. The only difference is if they are wide-band or narrow-band