Pocket pH meters perform on-site measurements of the environment, swimming pools, spas. Model PHT1: - PH meter - With 3 calibration points: 4, 7 and 10 pH - Estanco - Includes patterns and manual - Works with 4 1.5 AA batteries Model PXT4: - pH, redox and temperature meter - With 3 calibration points: 4, 7 and 10 pH - With replaceable sensor, temperature compensation and on-screen indication of calibrated buffers - Color LCD screen according to this in size, calibration or error. IP67 Tobacconists - Self-diagnosis message, battery level and calibration error - Includes patterns and manual - Works with 4 1.5 AA batteries