In at least one embodiment, an inner wall surrounding the connecting groove is provided with a first connecting thread, the first connecting part is provided with a second connecting thread, and the first connecting thread is configured to be threaded to the second connecting thread.

In at least one embodiment, the signal output end is provided with a first electrical contact of a concentric circular shape, the signal receiving end is provided with a second electrical contact corresponding to the first electrical contact, and the first electrical contact is configured to be electrically connected to the second electrical contact.

In at least one embodiment, a handle is provided on the detector body for a user to grip and use.

In at least one embodiment, the handle is provided with an uneven grip portion, which is used to fit the user's finger portion.

In at least one embodiment, a control board is provided inside the detector body, and the signal receiving end is electrically connected to the control board, and the control board receives a signal transmitted by the signal receiving end.

In at least one embodiment, a battery is provided inside the detector body, and the battery is electrically connected to and supplies power to the control board.

In at least one embodiment, a pointer meter is provided on an upper surface of the detector body and is electrically connected to the control board, the control board controls rotation of a pointer of the pointer meter based on the signal transmitted by the signal receiving end.