Extech PH90: Waterproof pH Meter

Features
Rugged waterproof (IP57) housing with Flat Surface Electrode for measuring pH in liquids, semi-solids, and solids. Does not break or get junctions clogged like the traditional glass bulb electrodes. Easy to replace sensor is perfect for field or lab use.

Rugged replaceable flat surface pH electrode for quick on-the-spot pH measurements
Simultaneous display of pH and Temperature
2 or 3 point calibration automatically recognizes buffer solutions (order pH buffers separately)
PTS (percent of slope) tells you when it’s time to replace your electrode (below 70% or above 130%)
Automatic Temperature Compensation
Data Hold, Min/Max, Auto Power Off, and low battery indication
Waterproof design (IP57) floats in water and protects the meter in wet environment
Complete with flat surface pH electrode, protective sensor cap, and two 3V CR-2032 button batteries