Features: Compact and pocket-sized design Easy to use and provides a quick measurement.High accuracy with ± 2% full scale accuracy Data hold function and built with Automatic Temperature Compensation (ATC) Auto power off.Wide range of applications in water quality testing Pre-calibrated at factory.Supplied with a screw driver for calibration if necessary Specifications: LCD display: 4 digits Measure Range: 0 ~ 19.99 ms/cm Resolution: 0.01 ms/cm Accuracy: ± 2% F.S. (Full scale) Automatic Temperature Compensation (ATC): 0 ~ 50 °C (32 ~ 122 °F) Operating Temperature: 0 ~ 50 °C (32 ~ 122 °F) Power Supply: 2pcs x CR1632 button cell batteries (not included) Material: plastic colour: blue Package Contents: 1 x water test pen 1 x screw driver 1 x English manual Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.