The Milwaukee PH51 Waterproof pH Tester is designed for all applications. Its IP67 Waterproof casing and double junction replaceable electrode make it suitable for heavy duty applications. These include saltwater, freshwater, and ponds. The modular design allows easy electrode and battery replacement and the Manual calibration on the pH51 model prolongs the battery life up to 1500 hours. The Milwaukee PH51 Waterproof pH Tester is supplied in a leather casing complete with calibration solution, batteries, instruction manual and screwdriver for calibration.