It's all you need for simple and reliable crop management and it's all within arm's reach! The Bluelab Combo Meter is a conductivity, pH and temperature meter all in one. The Bluelab pH Probe and the Bluelab conductivity/Temperature Probe are simply placed into the solution and the selected reading is displayed on screen. 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. Calibration of the pH is simple with the push buttons on the meter and fresh calibration solutions. Conductivity and temperature do not need to be calibrated as this is locked in during manufacture. Display options available in °C, °F, EC, CF, ppm 500 and ppm 700.