Since I'm close to exceeding the distance of the signal, I'm at 475 feet and the range is up to 500 ft. It sometime doesn't alarm to indicate delivered mail. I believe there are a few reasons for this. If the mail carrier doesn't completely open the mail box door or is setting in front of the box just right it may not alarm, add to that if my front door is shut that could also have an impact. I'm pretty close to their limits for working properly. I'm ok with that because of the walk I'd have to make to check the mail and fine none in the box. The other problem I've experienced with this is has just quit working without cause the light that indicates it's operating is off. I've tried resetting it and still nothing nothing. I'm not sure if there was a power surge or what but get this I take it apart and tinker with the board full of diodes and what ever all that soldiered stuff is called put it back to gather plug it back in and wala it works again! That's happen twice! I've had it a year now and it still works. If I could find something that might be better I would try it. For the price I can live with it.
