Waterproof, dustproof housing that floats is certifiable to IP67 standardsReplaceable sensor lets you reuse same meter body, saving you moneyHold function, Auto-OffAutomatic Temperature Compensation Our waterproof microprocessor TDSTestrs and ECTestrs offer push-button calibration and ±1% accuracy in a rugged waterproof housing. Never worry about losing your tester in a pond or tank; these testers float! Valox® housing and stainless steel electrodes offer good chemical compatibility. Replaceable sensors let you reuse meter body without losing waterproof protection.Measures TDS or Conductivity Range TDSTestr Low: 0 to 1990 ppmTDSTestr High: 0 to 10.00 pptECTestr Low: 0 to 1990 µSECTestr High:0 to 19.90 mS Resolution TDSTestr Low: 10 ppmTDSTestr High: 0.10 pptECTestr Low: 10 µSECTestr High:0.10 mS Accuracy ±1% full-scale Calibration One point push button Waterproof/Dustproof (IP67) Yes ATC Yes Electrode Replaceable Operating Temperature 0 to 50°C (32 to 122°F) Power Four 1.5 V batteries Battery life 140 hours continuous use Dimensions 6.5" x 1.5" dia (16.5 cm x 3.8 cm dia) Shipping weight 4.5 oz (125 g)