Thermo Scientific Orion Epoxy Body Double Junction Liquid Filled Green pH Combination Electrode, with Waterproof BNC Connector, 0 to 14 pH Double-junction, epoxy body pH electrode for durability and general purpose use RoHS compliant with no lead or mercury for normal disposal Refillable 3M KCl external reference for prolonging electrode life Ag/AgCl electrolyte for less noise (unwanted voltages) than gold or silver electrodes pH range 0 to 14