Myron L EP & EP10 Meters are compact, multi-range instruments that operate on the principle of electrical conductivity. They each contain a built-in cell cup and will quickly determine the conductivity of almost any solution. Both have dials calibrated in micromhos (¬µmhos) equivalent to the metric microsiemens (¬µS). Model EP features a second dial scale calibrated in megohms/resistivity for testing ultrapure water. Both are 3.4" x 4.5" x 4.0" (85 x 129 x 126mm) and weigh less than one pound (0.45 kg). EP series meters are completely self-contained. The built-in cell is automatically temperature compensated. Power is supplied by a 9-volt battery good for at least 2000 tests, or one-year shelf life. By using an RE-10 Range Extender (see W3800-1), the maximum range of each meter may be increased ten times.