Push-button calibration and high 1% full scale accuracy!Waterproof, dust proof housing that floats is certifiable to IP67 standardsReplaceable sensor lets you reuse same meter body, saving you moneyAutomatic Temperature Compensation 0 - 1990 PPMHold function, Auto-OffOur waterproof microprocessor TDSTestr basic offers push-button calibration and 1% accuracy in a rugged waterproof housing. Never worry about losing your tester in a pond or tank