The Milwaukee PH58 is a combination waterproof tester with advanced functions. The PH58 also includes the new model pH58 for simultaneous pH and ORP measurements and temperature, which is continuously displayed on the dual level LCD. The pH58 has a stability indicator and hold feature that freezes the display for easy and accurate recording. The large display also has graphic symbols to guide you through all operations. Calibration is performed automatically at 1 or 2 points using standard or NIST buffers.