Anybody know nitrous solenoids setups?

Came with my car and i took it off..
I got the line that comes from the tank>> solenoid>> T-fitting>>[straight] a second solenoid; [left?] a solenoid of some sort that i want to say is either a blowoff, or a purge setup... theres no wiring that goes into it.but has a a fitting for like a hose to come off it.
No part numbers on it
Anybody know what that 'left' solenoid or whatever is??
Gotta get pics soon and throw them up.

As far as wiring, i have a blue button [looks like a purge button in all the kits], a blue on/off switch, and a bosch thing that all the wiring goes to..

...or is that for a dry system to send pressure to the fuel regulator?