Ignoramus28889 fired this volley in
:

ARO alpha-body four way piloted solenoid valve?

Ig, I haven't looked at that pneumatic circuit yet, because mine works.
G

I don't know if the valve is "internal pilot" or "external pilot supply".
If you buy the internal pilot version, it's an easy job to convert it to
external pilot supply if necessary.

Otherwise, that description sounds right. MSC sells them. You need to
specify the solenoid voltage, and internal or external pilot (likely,
they don't stock the external versions, and will sell you a conversion
kit which is a screw and a washer).

LLoyd