The 105 Well Casing & Depth Indicator is used to detect metal well casing and measure total well depth. It offers both of these functions using one probe.
The probe has a strong internal magnetic assembly to detect well casing. When the probe is adjacent to magnetic metal (e.g. steel) a circuit is completed activating the buzzer and light. When the probe is no longer next to the casing, the signals stop.
A plunger at the bottom of the probe is used to measure total well depth. The light and buzzer activate when the plunger reaches the bottom of a well and is pushed into the probe body.
Well casing and well depths are read from durable Solinst laser marked flat tape; lengths to 600 m (2000 ft).