Invisible fence or wireless containment system for small dog.

[Westside88]

We have a large yard that we will be completely fencing, but needed something in the short term. We bought the type that has a sender that goes in the house with an adjustable radius, which we set on the max distance. It only took a couple days for our lab to learn that when she hears the warning beep it's time to turn around. I can go to the other side of the line and try to call her across and she'll stop just short of the line and sit and wait for me. In our case we would actually need a second unit to cover the back side of the house because it's a daylight basement type home and the drastic elevation change causes some issues, but most of our yard is in front anyway. I was actually surprised how well it worked and how quickly she learned the boundaries. Here's a picture of the one we bought.

[CastleRocker]

We have that same wireless one at our lot on the Long Beach peninsula, and a Pet Smart inground one at out house.  Both work well for all of our dogs, and use the same collars.

That being said, it will depend a lot on the dog.  A friend of ours had an Australian Shepard that had figured out that if it snuck up on the boundary, to where the collar beeps, and then takes one more slow and careful step to the vibration setting,  it could lie down right there until the battery in the collar goes dead...and then off it would go!  It was something to see.