This fence works very well on my 20lb terrier. It took him about two weeks to figure out were the fence was.I have the collar set on three.(one is just noise only). I have boundary distance to the fence set on about 12 feet.I can just say now i can let him out the back door with little or no worries of him running off. Without this fence he would not stay home at all.I did buy an extra 500' roll of wire. I made a big circle around the house. When I ran it under my gravel driveway i split an old garden hose and placed the wire inside and down about 3-4". I have had it installed and working for about a month. I am very happy with it.'