A waterproof, pen-style pH meter that reads pH across the full 0.00-14.00 range with 0.01 resolution while simultaneously showing sample temperature on its dual-line LCD. A single CAL button drives automatic two-point calibration against standard buffer solutions, and built-in automatic temperature compensation keeps readings accurate as the sample warms or cools. Its floating, splash-resistant body suits everyday testing of aquariums, pools, hydroponic reservoirs, and general lab or field water samples.