The Extech EC400 is a waterproof, autoranging ExStik® II meter that measures conductivity, TDS, salinity, and temperature using dynamic cell-constant technology with one electrode. It features six selectable units (µS/cm, mS/cm, ppm, ppt, mg/L, g/L), an adjustable conductivity-to-TDS ratio from 0.4 to 1.0, and self-calibration upon power up.

The meter has three autoranging conductivity ranges: 0-199.9µS/cm, 200-1999µS/cm, and 2.00-19.99mS/cm with ±2% FS accuracy. TDS and salinity ranges are 0-99.9ppm, 100-999ppm, and 1.00-9.99ppt. Temperature range is 0-65°C with ±1°C accuracy, and automatic temperature compensation (2% per °C) is included.

The large 2000-count LCD features an analog bargraph for trend indication and simultaneously displays conductivity/TDS and temperature. Internal memory stores up to 25 labeled readings for easy recall. IP57 waterproof rating, data hold, auto power off (disableable), and low battery indicator are included.

Complete with conductivity cell, protective cap, sample cup, four CR2032 batteries, and neckstrap. Applications include water treatment, wastewater, groundwater, aquaculture, and environmental testing.