Modern-Electronics m-e 41021 radio bell transmitter

For wireless extension of your doorbell, place the active transmitter next to the existing doorbell. As soon as it rings, the receiver connected by radio is activated. This is ideal for extending existing doorbells wirelessly. The response sensitivity is infinitely variable. The radio range depends on the receiver used, reaching up to 200 meters in open fields. It also works with telephones. There are indicator lights for battery and transmitting functions.