Leica Digisystem i780231 Manuel De L'utilisateur page 19

Digisystem, How to Use the Locator 18
Caution The absence of a positive indication does not guarantee the non-existence of a service.
Services without a detectable signal may be present.
The Locators can only locate non-metallic services such as plastic pipes, typically used by the
water and gas utilities, with the use of appropriate accessories.
Precautions:
Always excavate with care.