The working principle of latching relays is to use the magnetic field generated by permanent magnets to attract or release contacts, which can maintain their contact state after power failure, realizing power saving, heat reduction and reliability improvement, and are widely used in smart meters, energy management and so on. Hongfa latching relays are matched with customers of leading electric meter companies in America, Europe and Asia-Pacific, and has now become a major global provider of magnetic retention relays for electric power.