eSeasongear SALT-3000 Tester, Digital Salinity PPM Meter for Salt Water Pool and Koi Fish Pond Precalibrated at 3000 ppm salt (NaCl) Built-in ATC sensor for Automatic Temperature Compensation Built-in salt (NaCl) conversion factor for meter calibration Thermometer displays in C or F Please buy the SALT-3050 if you need a waterproof salt meter.