Thermo Orion 290A+ pH Meter. A handheld ion/concentration meter used for routine measurements of pH and mV with a two line digit LED display and ergonomic design. Features bidirectional RS-232 output, built-in 25 reading datalogger, memory for five pH autocalibration points, autoblanking correction, built-in electrode storage sleeve, custom LCD display (shows pH/mV/concentration and temperature simultaneously), prompting/diagnostic codes, concentration measurements, and internal datalogging function. Range (pH): -2 to 20. Range (mV): ±1600. Range (Temperature °C): -5 to 105. Resolution (pH): 0.001/0.01/0.1. Resolution (Temperature): 0.1°C. Resolution (mV): 0.1. Accuracy (pH): ±0.005. Accuracy (Temperature): ±1.0°C. Accuracy (mV): ±0.2 mV.