Solinst Model 101D [114123] Water Level DrawDown Meter with P7 Probe & Metric Increments, 100m. Solinst Model 101D Water Level DrawDown Meters  With P7 Probe - Metric. The Solinst 101D Water Level DrawDown Meter has all of the same qualities as the well-known 101 P7 Water Level Meter, with tSolinst Model 101D [114122] Water Level DrawDown Meter with P7 Probe & Metric Increments, 60mhe added feature of a drawdown mode. One simple toggle switches between static water level and drawdown measurements. Water level mode allows accurate depth to water measurements in wells, boreholes, standpipes and tanks. The drawdown function is used to monitor falling hydraulic head during low flow sampling, pumping and other aquifer/well tests. It also ensures a pump’s intake remains submerged during purging or well development. The 101D Water Level DrawDown Meter uses a corrosion-resistant stainless steel probe connected to clearly marked flat tape, fitted on a well-designed reel. It is powered by a standard 9 volt battery. In water level mode, when the zero point on the probe enters water, an electronic circuit is completed, activating the buzzer and light. The depth to water is then read off the tape. In drawdown mode, the circuit is reversed—the buzzer and light are triggered when the probe is in air. The battery test button can check the circuit in both water level and drawdown modes. The on/off sensitivity control allows the buzzer to be turned down in cascading water and ensures a clear signal in high and low conductivity conditions.