I have an above average sized city backyard and a dog that can climb like a highly motivated monkey. I really didn't want to chain her because she was an abused rescue and in my opinion has been through enough sadness in her life.I found this on and thought I would give it a try as a last resort. It really works great!I used simple small plastic wire ties to attach the yellow wire to the existing chain link fence.I followed the easy understand instructions provided to attach the transmitter and tested the collar using the supplied "tester" connector thingy.Now Daisy can run free and the neighbors have stopped coming to my house to tell me she is in their yard.