Suitable for water quality testing, such as drinking water testing, hydroponic planting, laboratories, aquaculture, sewage treatment, etc. This instrument is widely used in the following occasions: Measurement of total residual chlorine in aqueous solution, including free chlorine (Cl2) Hypochlorite (OCl-) and nitrogen compounds of chlorine (such as chloramine T) Measurement of residual chlorine in drinking water, cooling tower water, industrial and domestic wastewater. Process applications using chlorine as a pesticide and disinfectant, such as industrial water quality control, hot spring water, etc. Maintenance: After the test is completed, dry the water and keep the motor clean If it is not used for a long time, please remove the battery and cover the electrode protective cover High-definition LCD display Large screen display, clear values and easy to read, High-sensitivity probe High-sensitivity electrode probe, measuring water quality High precision, automatic temperature compensation, reducing errors Battery model: lr44 (3pcs) Colour:As Shown Material:Plastic Package Contents: 1x water quality test pen 1x ph powder pack 1x ORP powder pack 1x 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.