I found this device on the street, several cars did go over it.
I checked resistance just something about 0.6Ohm, does not change with temperature as it seems.
Diode test shows both poles are equivalent.
Block is steel or nickel maybe, a magnet attaches to it. No reed contact.
Plug is 2.3mm. Two poles.
Wild guess: Some sort of antenna? Some inductive thing? But cable is not shielded...
Your guess?
Thanks,
Carsten