Would you like the complete invisible fence system? Why am I offering it? My 2 dogs were able to roam an acre or more with only the invisible fence (after being trained). This worked for several years until my boy dog decided to cross. He walked across it, he didn't run across. He also came back across the invisible fence. Guess his eyes were bad and he didn't see the invisible fence.
My friends (they were my friends) used the collars on themselves to test it and they did not want to cross the invisible fence line.
I don't have the collars because I gave up and threw them away. Today I removed the Invisible fence hardware that makes the collars work & this is the most expensive part of the system.