Please feel free to buy our products, we have excellent after-sales service.Specifications:EZ9902RangepH: 0.00 to 14.00 pH; EC: 1 to 19999us/cm; TEMP: 0 to 60.0 °C / 32.0 to 140.0 °FThe resolutionPH: 0.01 pH; CE: 1 μs / cmAccuracy (@ 25°C; / 77°F)pH: ± 0.05 pH; TEMP: ± 0.5 °C CE: ± 2%CalibrationpH 6.86 points: accuracy ± 0.1 pH.6.86 / 4.00 (6.86 / 9.18) points: accuracy ± 0.05pH.6.86 / 4.00 / 9.18 points: accuracy ± 0.02 pH.CE calibrated by the factory (1413μs/cm)Temporary compensationAutomatic temperature compensation (0-60°C)Battery / Auto power offButton battery 3 x 1.5 V (not included).Automatic power off: 5 minutes.Low power protection system / battery indicatorEnvironment0 to 60.0 °C (HR 100%)Dimensions / Weight183 x 37 x 37 mm (7.2 x 1.5 x 1.5 inches).Package contents:1 x digital water pen.If you would have any questions, please feel free to contact us. we will Try our best to make the things right for you!