ERA-EXTEND-A-CHIME Long Range Wireless Doorbell Extender This extender kit allows you to extend the listening range up to 3/4 of a mile using most any existing wired doorbell chimes. using a 16 volt transmitter. Hear your doorbell downstairs, in a back office, a garage, pool house, barn, warehouse, neighbors house - your options are virtually limitless as long as you are within 4000' range of the transmitter. You can add as many doorbell plug in receivers (ERA-RXPG) as you like. Need a portable doorbell? The ERA-VPRX may be purchased separately that you can take with you on the go. How This Plug In Wireless Door Bell Extender Works Wire the 1.75"Hx2.00"Wx0.75"D transmitter to your existing doorbell and pair the transmitter to the plugin receiver included in the kit. Inside your wired doorbell there are typically three screws. One for the front door, one for the back door, and a "common" terminal that comes from the wired doorbell transformer. There are three wires on the transmitter, one for the front door, one for the back, and one for the transformer. If you only have one door, you will only use the front door wire and let the other wire hang loose. When a visitor presses the wired pushbutton outside your house or place of business, the wired chime will ring as normal, and at the same time, the plugin wireless receiver(s) will also. The transmitter fits inside the cabinet of most wired chime units, if not then you can it with included double sided tape. The receiver that plugs into a standard wall outlet & has three operational modes: Strobe only mode: a bright flashing strobe that flashes for approximately 15 seconds when triggered. Sound only mode: 12 different tunes/melodies to choose from. Strobe & sound: the strobe will flash for about 15 seconds and the selected melody will play for the length of the chime. A great way to convert your current chime into a doorbell of the hearing impaired and deaf.