Friedl&-D936-Libra-Telephone-Doorbell-Ringer-Friedl&-D936-P-Buy-Friedl&-D936-Libra-Telephone-Doorbell-Ringer-for-use-with-all-Libra-door-bells-The-transmitter-simply-plugs-into-a-telephone-in-order-to-activate-your-Libra-door-bell-when-your-telephone-rings-P-Friedl&-D936-Libra-Telephone-Doorbell-Ringer