It actually works! My son rescued a part Lab part Boxer pup after his mom was ran over at my son's school. Soon, he outgrew the garage and was living outside. Then he got old enough to start wandering into the neighbor's yard and the search was on to contain him. I had looked at these type setups because I don't like fences or leashes. I want him to be able to run and play. This was the cheapest head unit I could find, but it appeared to be the same as the more expensive models, so I got it and upgraded the cable to this: http://www..com/1000ft-14AWG-Professional-Grade-Dog/dp/B00CA5KV0W?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o06_s00 and it was worth it. My son just hit part of the wire with the weed eater last Saturday and it put some scratches on the insulation but it was fine! We manually buried 800+ feet of the cable one weekend and bought a pack of white pin flags since there were not enough provided. That was about an acre. We came back toward the house and went around the pool but made it where he can still get up on the deck. I hooked up the unit and tested it and it was pretty easy. Read the instructions. One complaint I have is the clamps used to hold the wire in the unit are weak and do not hold the heavier guage wire as well as I would like. This lab pup is crazy and had been used to running wherever he wanted for many weeks, so I was skeptical. But the kids and my wife were consistent to let him out of his pen and train him what would happen if the boundary was approached. It took several days because he was used to running all over the place. And we had to adjust the width of the boundary and up the level of the collar once. But, I have to say that I am well pleased. He knows he can't follow us or other animals out of bounds. But he enjoys his 1 acre to play be a dog and my front yard and landscaping arent being destroyed. Win Win.