This is a pneumercator board for tank management/liquid level management leak detection. The board itself they sold on eBay is worth a lot of money I’m just curious if these modules are worth anything or what’s inside of them if anybody knows. And if so what would the class or grade be. They are heavy

If you can find a market for a board, selling is almost always the best way to go to make the most money.

Not sure what is in those black boxes but as far as scrap value this looks like low, maybe mid, grade.

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Here to learn more so I can recycle more
My grades are my own opinion and not an official grade from Boardsort

My conundrum is I’ve been trying to sell it for a couple years, there’s no reason I can’t hold onto it and continue to try to sell it but I am beyond curious to know what is in those boxes. Knowing it’s probably not anything to be excited about.

Possible clue to black box module contents.
It would be great to have a photo of the bottom. It would really help
Why? The circuit board traces will be a clue to the black boxes.
Here's what I see. 8 diodes and 8 resistors. That is typical input signal conditioning.
Could be from the sensor inputs. My point is that that number 8 is a typical data or address bus number for a microprocessor/microcomputer.
Also the gray ribbon cable seems to be a 16 bit output from the large black module.
Again 16. Typical data or address bus number.
There is a good possiblity a microprocessor chip is in that big module with some support chips.
Tech companies protect thier designs with modules like that. Also. Keeps unqualified technicians out. And ensures no tampering. Reducing possible liabilities.
If your going to scrap it. Crack it open. Might be surprising.
But. You may find the whole module in a black expoxy like resin
I personally would like to see you post it. If you open those 3 modules.
This forum is for education. It can help a lot of e-scrappers.
Might put you into low peripheral grade.