Non Implantable Field Detectors

So when I was looking at the xEM implant I noticed the field detector that came with the xEM was encased with something. Is it biocompatible material or is it just normal plastic or glass? I know its not sterilized at all but I was just curious on what it was.

Plastic. No chip, just an antenna and LED that you can use to find the best position for scanning your new implant. Since it has an LED, it’s easier to find the right position on a reader than rubbing your hand all over the reader til it beeps lol
Plus you can approach wild readers with it and find out if it’s LF or HF.

It’s like an XLED but not safe for implanting.