The EXTECH PH113 Waterproof Refillable ExStik pH Meter provides accurate and reliable pH measurements in a variety of applications. Its refillable electrode ensures long-term performance and eliminates the need for frequent replacements. The flat surface electrode is suitable for measuring pH in liquids, semi-solids, and solids, while the CAL alerts and memory functions help maintain accuracy and track changes over time. The waterproof design and floating capability make it ideal for use in wet environments, and the interchangeable probes allow for measurement of chlorine and ORP. This meter is a valuable tool for water treatment, aquaculture, and other industries requiring precise pH monitoring.