Neptune ALD (leak) Sensor Opened Up?

[Harry Muscle]

Does anyone have any pictures of the inside of the Neptune ALD or leak sensors? I've read that it's a passive device but I've also read that extending the wire requires four conductors which would suggest it's an active device after all. I thought I've seen a thread long time ago where someone posted pictures of the probe taken apart but now I can't find it.

Thanks,
Harry