Solinst-Model 101D- Water Level DrawDown Meter
Both static water level and drawdown modes in one Meter
Measures both static water level and drawdown modes in one meter with one convenient toggle makes it easy to switch between the two functions. When in DrawDown mode the probe signals in air instead of water. This is a great feature if you need to know when levels in a well are dropping. Tape lengths up to 5000 ft. (1500 m).