Electronic dog fence

We have had one for the last nine years. They are mfg by Pet Safe. I bought two transmitters so it would cover all the way around our house. One is mounted near the ceiling in the garage and the other one is upstairs at the opposite end. Since it transmits in a circular pattern they are positioned so the circles overlap. After about a month of our big dog testing the white flags he learned very quickly his boundaries. Today I do not even bother to put his collar on because he will not venture on his own out of those imaginary circles. I also had it set on the strongest shock.

And yes, I tried it on myself to see if it was too much for him. It got my attention for sure.