Displacer actuated external cage switches are external cage units that utilize a single switch mechanism for level alarm or control functions in higher-pressure applications. Liquid level movement changes the buoyancy force on a displacer suspended from a range spring. The force change on the spring causes it to expand or contract, moving an attraction sleeve into or out of the field of the switch magnet, actuating the switch. It is used in hydraulic accumulators, natural gas receivers and separators applications.