A sounding rod is a section of small pipe used to determine the depth of fluid in a tank (the tanks sounding). Sounding rods are sent down a sounding tube until they hit the sounding plate. For ease of handling as well as to handle curves in the sounding tube and facilitate storage, sounding rods are generally collapsible, being formed of short sections of pipe connected by hinges. The body of the rod is usually graduated in inches or millimeters, increasing from the bottom. By reading off the highest value of fluid on the sounding rod, a tanks sounding can be determined (and thus the tanks condition of load).