Wireless Dog Fence by PetSafe
Product Review (submitted on September 14, 2011):
This was a must have for my very nosy/smart German Shepherd. She loves going in our neighbors yard and chewing their shews and bringing her daily finds back in our yard and on our porch only to bend chewed later that day! (Which is why we leave nothing on the porch) And this was such a blessing! It took her all of one time of being shocked that she learned to associate beeping with being shocked and she knows to turn and run to the house! My only complaint is the batteries die pretty fast but that's not a big deal batteries on here for cheap.