COM-80 water tester pen for hydroponics, pools, spas, aquariums, water and more

HM Digital COM-80 Electrical Conductivity (EC) and Total Dissolved Solids Hydro Tester, 0-5000 ppm TDS Range, 1 ppm Resolution. The COM-80 is an economically priced, reliable EC/TDS meter (ppm pen / nutrient tester) that is ideal for testing applications such as hydroponics & gardening, pools & spas, aquariums & reef tanks, water ionizers, drinking water and more. Also great for commercial applications, such as boilers and cooling towers and filtration and purification systems. Four scales: EC: µS, mS; TDS: ppm, ppt. Automatic Temperature Compensation (ATC). Water resistant Used only a couple times.