first come join us on estim chat discord.
https://discord.gg/S9qPG4MUcd
second, the abox likely has 3.5mm phone, and if that "cheap plug" is too loose then it's likely a 2.5mm phone mono connector.
https://www.amazon.com/uxcell-Connector ... B005KP2AJY
is close, but you need a pair of mono adapters, and i can't find more time to search.
also you can use the cheaper trode, but you also get what you pay for so keep an eye on it, discoloration in the foils, after cleaning, and pealing edges, should be discarded.
and honestly i personally just buy a batch of these, cut and resolder the leads to suit my machine
https://www.digikey.com/en/products/det ... 20/2646629
conrad should also have them if you are in europe