The Bluelab pH Meter is used to accurately measure the pH value of a solution. Simply place the Bluelab pH probe into the solution and the reading will be displayed on the screen. As the meter is portable and does not need a power supply to operate, it can be used anywhere and anytime to help you manage your crops daily nutrient requirements. Calibration is simple with the push buttons on the meter and fresh Bluelab calibration solutions. Benefits Lightweight and portable Large easy to read display Simple push button pH calibration Replaceable double junction pH probe included Successful pH calibration indicator Over range and under range indicators 2 x AAA alkaline batteries included Auto off function Low battery indicator