The pHep¨ 4 tester is for users that require the greatest accuracy and features while staying economical. This model has BEPS (Battery Error Prevention System) as well as user selectable automatic shut-off, replaceable pH electrode cartridge, stability indicator and automatic calibration. Waterproof and designed to float with tactile grip casings. Automatic Temperature Compensation built in as well as Hold function. Efficient two button operation with a temperature in ¡C or ¡F.