I chose this product because its scope looked good from the description and evaluation. Bell installed on the pillar at the entrance to my property. Proper functioning while the button of the radio signal through the pillar, 30 m free field and the wall of the house (not particularly thick). A simple touch of the button is enough to trigger the signal, a small blue LED lights up to confirm the order. It seems airtight. For better performance over time, I have not glued the button directly on the pillar (plaster). I fixed a small plate of plexiglass and glued the button above. Pleasing aesthetics, classical melodies, but with a great selection. The only drawback is that monopolizes the bell socket. The programmed ringer is lost due to a power outage. The advantage of the mains power supply is a battery saving. The bell that I had previously had intensive battery and no way, without testing, to see that the batteries were exhausted. The button had not endured the rain and had finally give up the ghost.