Milwaukee MA9011 Refilling Electrolyte Solution 3.5 M KCl is a ready-to-use solution for refilling pH and ORP electrodes, ensuring stable reference potential and accurate measurements. 3.5 M Potassium Chloride (KCl) in distilled water liquid, ready-to-use for refilling and maintaining pH and ORP electrodes (including double-junction types) stable at room temperature, typically 50 mL or 100 mL