All right, so how does DEF work exactly in a diesel exhaust system?

So DEF is essentially a part of a complete system.

So if you think about the diesel engine, the exhaust system, it's one component of that process.

So you have the engine that's creating heat, creating exhaust, and that could go through multiple pieces of the system.

So that exhaust may go through an EGR, may go through a diesel oxidation catalyst, which is basically going to Think of that similarly to a catalytic converter in a passenger car gasoline vehicle.

There's also a component that's the diesel particulate filter.

And then you start where the DEF comes into play.

Can you tell us about what those are and what they mean to end users?