The Instant Wireless Pet Barrier.

This wireless pet barrier trains your dog to stay off of furniture and out of forbidden rooms without complicated installation or physical barricades. Simply strap the collar on your dog and place the wireless transmitter under a couch, behind a garbage can, or attach it to a wall. The transmitter creates a 2' to 12'-diameter zone that, when penetrated, causes the collar to produce a tone and a harmless, mild static energy pulse that prompts the animal turn back. After only a couple of exposures to the barrier, the dog will learn that the restricted area is not to be approached. The transmitter has two modes, allowing you to permit access to one dog and not another (additional collars sold below). Collar fits dogs weighing 5 to 200 lbs. Transmitter requires three AA batteries. Includes two CR2032 batteries for the collar. Transmitter: 4 3/4" Diam. x 1" H. (10 1/2 oz.)