Fantastic

We live in an old house with thick stone walls so wiring a backdoor bell you can hear at the front of the house is very difficult and most wireless bells don't work through thick walls or the transmitter fails or both!
Installed this in 10 minutes - an easy job - and placed one bell in our kitchen at the rear of the house and one in the study at the front. Both worked clearly despite three walls and four doors in the way in the case of the study one - 25 meters away from the bell push