This pH meter is an accurate, waterproof (IF67) and easy to use digital pH pen. Provided calibration fluid and easy to calibrate with the adjusting screwdriver at pH 4 & pH 7. With a special moist sponge inside the protective cap to keep the electrode moist thereby increasing the life of the unit. Replaceable electrode make convenient for maintenance and money saving. Energy saving with the auto power off within 5 min if unused.