The Bluelab pH Meter is used to accurately measure the pH value of a solution. Simply place the 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. It is easy to calibrate by using the push buttons on the meter and fresh Bluelab calibration solutions. Main Features Quality pH probe included Simple push button pH calibration Auto turn off function Large 13mm (1/2in) digital display for easy reading Low battery indicator 2 x AAA batteries Light weight and portable How many meters can you find that have a 5 year guarantee? These meters have proven themselves in the horticultural market for years. The guarantee is our badge of proof - reliability and accuracy!