Myron L pDS Meters are compact, lightweight, self-contained conductivity/pH meters. They contain a built-in conductivity cell with a replaceable pH sensor. Models EP11/pH and M6/pH have dials calibrated in micromhos (equivalent to the metric microsiemens) and in pH units. They will quickly determine the conductivity and pH of almost any solution. Both are 3.4" x 4.5" x 4.0" (85 x 129 x 126mm) and weigh less than one pound (0.45 kg). pDS Meters are completely self-contained. The built-in conductivity cell is automatically temperature compensated from 50° to 160°F (10° to 71°C). Power is supplied by two 9-volt transistor batteries good for at least 2000 tests or one-year shelf life.