Anybody ever make their own sensor pad for moisture tester?

I’ve got an AgraTronix moisture tester on my baler...the sensor pad in the bale chamber has a little hickey on it and I’d like to replace it.

Looking online I’m seeing that you have to buy a kit which includes cables, hardware and cables. All I need is the pad which is why I’m asking if anyone has made their own replacement? Not sure what the pad is made of. Any thoughts on this?

Anybody ever make their own sensor pad for moisture tester?