The Bluelab? Combo Meter is a conductivity, pH and temperature meter all in one. As the Bluelab? Combo Meter is portable and does not require a power supply to operate, it can be used anytime and anywhere to help you manage your crops daily nutrient requirements. Simple push button pH calibration. Successful pH calibration indicators. Low battery indicator. Over range and under range indicators. Display options available in degrees ?C & ?F, EC, CF, ppm 500 and ppm 700. Supplied with 2x AAA alkaline batteries, replaceable double junction pH probe and solution sachets.