The Solinst Sonic Water Level Meter is a portable, acoustic ranging instrument designed to simply and quickly measure depth to static water level in a well, piezometer, sounding tube, or any closed pipe. The Sonic Water Level Meter reports static water level measurements without having to put any instruments down the well, eliminating any introduction of chemicals and the need to decontaminate equipment or wells. The Solinst Sonic Water Level Meter works in straight or crooked pipes, and is ideal for wells with difficult access. Depth measurements to 600 m (2000 ft) are possible. The Solinst Sonic Water Level Meter consists of a Control Unit and connected Probe. The Control Unit has a clear LCD display, keypad, and comes with 6 AA replaceable batteries. The Control Unit keypad has buttons to turn the Probe on and off, read the depth to water, and controls to scroll through and set other parameters. The Probe connects to the Control Unit with a 1.8 m (6 ft) cable. The Sonic Water Level Meter Probe is designed to sit in the vent opening of a standard well cap, or the opening in a Solinst 2" Locking Well Cap. For measurement in larger diameter openings, each Sonic Water Level Meter includes a plastic disc to cover the well opening. This ensures a strong signal and accurate water level reading. The Sonic Water Level Meter works by the Probe transmitting a sound wave into the pipe or well and measuring the time it takes for the pulse to return after making contact with water. The distance is calculated using the speed of sound and time. Since the speed of sound varies with temperature, a temperature sensor is located in the Probe to adjust for variations. To account for different well diameters, offsets, well obstructions or features, the Control Unit allows you to input measurement parameters to get the most accurate water level.