What exactly is a Vapor Canister Purge Valve?

[unity]

And what does the purge system do? I noticed when comparing notes with Tommy that his canister purge parameters are very different from stock. So I guess this is a two part question. What is it and what does the system do exactly?

FORD PART NUMBER: E4ZF-9C915-AA

 

[Aquabrit]

It's described in my service manual... I'll take a pic.

 

[chicken]

uhhhhh yup ^^

 

[unity]

Thanks.