What are the differences among these pneumatic valves?

What are the differences among solenoid valve, solenoid air pilot valve and air pilot valve?

I read a powerpoint slide from a website (Please see attached picture). I believe I know what is solenoid valve, but what are solenoid air pilot valve and air pilot valve?

Please help
Thanks

"Air pilot" has two hoses pushing on the pilot valve which in turn "relays" air flow to the main spool or poppet valve. So instead of wires coming from this spool valve, you have air lines. The control of the air can be anything but is external to the spool valve.

"Solenoid operated air piloted" has two wires going to each end with the electric solenoid and integrated air pilot assist (usually a poppet) built into the valve actuator assembly.

If you get to dissect various spool valves, study them and play with the pieces, you will find amazing little feats of engineering inside, and valves within valves in reality.

Thanks for your good, fast and clear answer

Also, if you see "direct acting" that means a solenoid (electric magnet) donut mounted to slip over one or both ends of the main spool shaft or when only air symbols exists, (no pilot), air directly drives the main spool or poppet. Look at Macvalves.com Crappy website, but the pictures of their designs are pretty cool to read about once you drill into a product category. And they are far and above my fave for reliability, and flexibility in design. It does take work to generate correct part numbers, but they can do about anything imaginable big or little valves and it will do it for years trouble free.