[Richard]

I do not have a part number other than what you see in the photo.
   

It is a simple 12V activated solenoid. It is not a three way solenoid.

Here is an example. https://www.mcmaster.com/pneumatic-valve...le-acting/  Look at valves G and H. You can find them cheaper now that you know what you are looking for.

Or if you want to go a different way https://www.amazon.com/4inch-Normally-Cl...B074Z5SDG3