Review on Wireless Doorbell Chime - AVANTEK Mini Waterproof, 1000 Feet Range, 52 Melodies & 5 Volume Levels With LED Flash by Davon Clark

It was sooooo easy to sync up. Took less than a minute. Was concerned I wouldn't hear the bell ring on the third floor since the receivers are on the first and second floors. I can hear it loud and clear.I'm sure the adhesion would work on a smooth surface, but my door bell is on a stucco type wall so didn't stick very well. I was able to screw the top into the wall and bought a heftier outdoor double stick tape to put on the bottom portion.Only negative is if you want to screw the bell into a wall the screw holes are not drilled, you have to do it yourself.