With dual electrode inputs, the Orion 720Aplus allows two measurements at the same time, perfect for a busy, multi-user laboratory. Measure pH with ROSS ResolutionTM to 0.001 pH units. The pH autocalibration feature recognizes five pH buffers using built-in buffer/temperature tables. Express concentration results to three significant digits. Full five point concentration calibration with automatic blank correction improves results of low level measurements. User prompting walks you through each meter operation. Store data using the internal datalogger or print, via the RS232 with the optional Orion 900A printer or computer. GLPdoc records calibration parameters such as slope, temperature, mV of standards, and time and date of calibration, providing a convenient record-keeping system compatible with "Good Laboratory Practices". Three (3) year meter warranty.