Range: 0.0-14.0 pH, Resolution: 0.1pH, Accuracy : +-0.1pH, Life: Approx 7000hours of use, Dimensions: 150mmx29mmx20mm Digital Pocket Pen Type PH meter with LCD display. Package Includes: 1x PH Meter, 2x Calibration Powders, 1x Screw Driver, 1x Carry Box Operaton: Remove the protective cap, First rinse the electrode with distilled water, and such it with filter-paper, Turn on pH by ON-OFF switch located on the top of battery case. Immerse the Ph meter electrode in the solution to be tested. Stir gently and wait for the reading to stabilize. After use, switch off pH, Use the distilled water clean the electrode and replace the protective cap. Usages: ideal instrument for aquarium, fishing industry, swimming pool, school laboratory, food & beverage etc. Important: The instrument's pH range must be recalibrated whenever the electrode has been used for long time from the last calibration. The electrode has been used in particularly taxing conditions. The utmost accuracy is required.