I have two invisble fencing units. One is new with a new black collar and the other is used with no collar. Our dogs had passed away and the wall unit had no longer worked. They run about $250 each NEW and Im willing to negotiate for the two or buy one each. The price is flexible. They may need batteries. Price will be as is, but I am confident they are good. If you want any questions or interests, please leave a phone number and name. I can never figure out how to respond by email (sorry)