The one in the picture is one that adjusts the fuel pressure.
I am pretty sure, it is.
I have had both of them.
A Toyota one, that adjusts a few things, and that is connected into the module just behind the RHS battery, on the 120 series.
Then I took it off.
Then I fitted one almost similar to what you have shown
It connects between the fuel pressure sender, via a male and female plug / socket.
Then I took that off.
WHY ?
Well, even though the engine appeared to make more power and TQ, the auto box, simply shifted down a gear.
So to me, I wasn't getting any advantage.
If it was fitted to a manual, then maybe the impression, and feeling would have prompted me to keep one of them.
Just my thoughts of when I had them.
Now, I wouldn't bother an an auto.
Gra.