The Oakton EcoTester EC is a portable conductivity meter that has automatic temperature compensation for accurate readings in fluctuating temperatures, one-point manual calibration, and automatic shutoff that extends battery life. The two-pin chemical-resistant stainless steel sensor has a probe guard and transparent protective cap. The waterproof, dustproof housing meets IP67 ratings. This meter is used for water-quality applications such as aquaculture, marine-fish aquariums, koi fish ponds, food processing, pools, spas, and environmental monitoring. Conductivity meters, also known as electrical conductivity (EC) meters, measure the ability of a solution or material to conduct an electrical current. This measurement helps determine if the solution is, for example, contaminated or contains too much saline. In general, pure solutions, such as distilled water, have low conductivity. More saline- or nutrient-rich solutions, such as seawater or fertilizers, have high conductivity. Conductivity measurements are often used with total dissolved solids (TDS) measurements, which are typically expressed in ppm (parts per million). TDS consist of dissolved minerals and salts. To determine the amount of TDS, conductivity is measured, and the result is converted to a TDS measurement. Different meters provide results for conductivity, TDS, or both, and the application determines meter selection. Conductivity meters are used in research laboratories and a variety of industries, such as water-quality testing, waste-water treatment, hydroponics, agriculture, aquaculture, and cosmetics manufacturing. Oakton Instruments manufactures scientific instruments for research, industrial, and educational uses. The company, founded in 1991 and headquartered in Vernon Hills, IL, specializes in meters, electrodes, and transmitters.