The electrolyte level in refillable electrodes should be checked before performing any measurements. If the level is low, refill with the proper electrolyte solution to ensure the correct electrode performance. This simple maintenance helps guarantee the efficiency and precision of your refillable electrodes. Electrolyte solutions are also available in FDA compliant bottles.Description Electrolyte Solution, 3.5M KCl + AgCl Bottle 4 x 30 mL bottle