Wireless dog fence

I used to have a labrescuenc wireless system. If I remember right each transmitter did a 300 ft radius. It worked good until I had more dogs than I had collars for. Then the ones without collars would tempt the others to run off. These were labs also. There were different strengths to set it at. Full strength for labs. All in all it worked good. I now have a 7 wire high tensile fenced in area in my yard/timber. Definitely don't have to worry about them now.