Uasage: Test the purity of filter water quality, check your water filter performance, check its hardness, make sure you always drink pure water.(Please get the promo code on product page when purchasing to get a better price.)Quick and Accurate Readings: Turn it on, dip in liquid and read the display, no need to work with color charts or test strips; a large LCD display makes it easy to read.3 in 1 function: temperature switching (automatic temperature compensation); Shift between TDS and conductivity with the "shift" switchPortable Design: Pocket pen style and compact carrying case make it easy to put in your pocket or bag and go on the go. anywhere.Wide Application: Ideal for water purifiers and filters, food and beverage (food, vegetable) quality monitoring, swimming pools and spas, aquarium, hydroponics.