Extech PH100 pH meter. Meter with flat surface electrode for fast and easy on-the-spot pH measurements. Built-in Smart chip offers advanced functions and features to a stick style pH meter not found anywhere else. RENEW feature that tells you when itís time to replace your pH electrode. CAL feature that tells you when itís time to recalibrate your meter. Flat Surface pH electrode that is completely waterproof and rugged enough to withstand harsh environments. Analog bargraph originates at neutral point (pH 7.00) to conveniently view trends in acidity or alkalinity. Temperature measurements with Atomatic Temperature Compensation. 1, 2 or 3 point calibration automatically recognizes buffer solutions. Order pH buffers separately. Complete with flat surface pH electrode, protective sensor cap, sample cup with cap, four 3V CR-2032 button batteries, and 48" (1.2m) neckstrap.