What did this man measure?

Hello everyone,

I came across you while searching for a construction forum.
And I hope you can help me with my concern.

Today, a man with a strange device was on our property. However, we had not "ordered" him.
He had a monitor/computer in front of his stomach and then dragged this "thing" on the ground behind him as he was leaving.



I would be very glad if someone can say exactly what was being measured here.

Thank you very much in advance.

Gas line checked for leaks.
Is done regularly every few years.

Gas pipeline checked for leaks. Done regularly every few years.

But there is no gas pipeline running there.

Sure?
Not even to the neighbor?
Try searching for Gasschnüffler, you’ll find similar pictures to yours.
The gas suppliers use it to check their pipelines.

Why are you taking a photo instead of simply asking him what he is doing?

Why are you taking a photo instead of just asking him what he is doing?

Wonderful....!!!!!!