The Myron L DS Analog Handheld 4 Range EP-10 Meter is a trusted and popular DS Meter. DS Meters provide fast, accurate, on-the-spot measurements of total dissolved solids (TDS) or conductivity. This instrument is capable of testing both ultra-pure and ocean waters. It has four conductivity ranges for easy readability and the most sensitive range including resistivity equivalents. The EP-10 Meter is ideal for DI water systems.