DESC: Panasonic's vision of the digital future is driven by the needs and aspirations of its business customers and millions of consumers around the world who use Panasonic products every day. Panasonic shares their dream to live a fuller life by providing ways of working smarter and enjoying the rewards of technological advances.??KX-TGA420B is one of the stations (extensions) and must be used with a KX-TG4000B/KX-TG2000B base unit (operator). It is necessary to register this station unit to the base unit before use. The station unit does not work without the base unit.