Abstract: A one-piece seal ring for locking an electrical watt-hour meter into the socket of a meter base. The seal ring includes a locking mechanism which once locked cannot be unlocked without cutting or breaking a portion of the lock. The seal ring and locking mechanism are entirely manufactured of one-piece construction using a brightly colored, flexible and resilient thermoplastic, enabling the locking seal ring to be inexpensively manufactured with little or no manual labor using modern thermoplastic injection molding in automated machinery. The coloring of the lockable seal ring, being contrasting to that of the flange of the meter, provides structuring to provide a visual signal of an unlocked or missing seal ring on an installed electrical meter.