Thermo Scientific Orion Star A211 Benchtop pH/ISE/mV/Temperature Meter Thermo Scientific Orion Star A211 pH Benchtop meter with pH range: -2.00 to 20.00 Large, backlit graphic LCD display shows pH/mV/RmV and temperature along with electrode status, time, date, sample ID, user ID and calibration points AUTO-READ locks in the stable reading on your screen, ready indicator alerts when readings are stable, and timed reading gathers data in specific time intervals Included electrode arm and newly-designed probe holder make it easier to maintain and place probes into samples Works with almost every AC power source with the included universal power adapter, or use four AA batteries (sold separately) to run the meter on DC power