Unique Glass Membrane - The PHE-16 pH Electrode uses a special H glass membrane, with better accuracy and repeatability in strong base solutions; the hemispherical sensor is built tough and highly resistant to general impact. Silver Ion Trap Reference System - The PHE-16 pH Electrode uses a Silver Ion Trap reference system. On top of the Long-Life reference system, a silver ion trap is added to prevent the junction from being blocked by silver sulfide. The electrode uses a BNC connector, compatible with any labForce® pH meters.