PH90 is a waterproof pH meter. Featuring a rugged, waterproof (IP57) housing with Flat surface electrode for measuring pH in liquids, semi-solids, and solids and also displays temperature on the large LCD. The electrode does not break or get junctions clogged like the traditional glass bulb probes. Easy to replace sensor is perfect for field or lab use. Features a 2 or 3 point calibration, which automatically recognizes buffer solutions, and PTS (percentage of slope) tells you when it's time to replace your electrode. Complete with Flat surface pH electrode, protective sensor cap, and two 3V CR-2032 button batteries (pH Buffers are required for calibration - sold separately).