Quick and Accurate Readings, - Just turn it on, immerse in about 1 inch of water and read the display, the large digital display makes it easy to read. Automatic calibration, no need for any adjustment screwdriver, it only takes 1-3 seconds to complete the automatic calibration calibration, measure the total dissolved solids (tds) in the water, know exactly when to replace the water filter. The handheld and compact carrying case makes it easy to put in your pocket or bag and take it with you. for home and laboratory TDS testing applications including drinking water, swimming pools, aquariums, hydroponics and more. No need any adjustment screwdrivers, just finish the calibration with Auto calibration with 1-3 seconds, Measure total dissolved solids in water(tds), Know exactly when to change water filters. Range: 0~9990ppm Accuracy: +/-2% Battery: 2 x 1.5V LR44 Button Cell Batteries (included) Size: . 5.51 x 0.79 x 0.6 inch Colour:Navy blue Material:plastic Size:about 13.9 x 2.3 x 1.4cm Package Contents: 2 x TDS Meter 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.