"The CDB-387 is a microprocessor-based, benchtop conductivity, resistivity and TDS meter. The unit has a large LCD display and membrane keypad for easy operation. The meter features automatic temperature compensation, programmable temperature coefficient, recorder output and bi-directional RS-232C output. The CDB-387 measures 5 conductivity ranges, 2 resistivity ranges and 4 TDS ranges. The CDB-387 will automatically select the most suitable range to provide maximum resolution. The CDB-387 operates off ac power or a 9 V battery. The 9 V battery serves as a back-up to retain calibration data, even in the event of a power failure, and allows for portable field measurements. The unit is supplied with a glass dip-style conductivity cell with an integral temperature sensor, K = 1.0, calibration solutions and 9V ac adaptor."