In this image it shows a crew member using a moisture meter. Moisture meters are used to determine the actual moisture content of various materials. In this image SERVPRO is using it to determine where the water migrated in this carpet.
The moisture meter being used is a penetrating moisture meter which have probes to allow testing within wall cavities and underneath wood flooring systems, causing minimal damage to the surface.
On a water loss you will see SERVPRO's crew using these types of tools to help do our job correctly. We pride ourselves on doing the best for customers.