The CAT200 Indoor Boundary can be used with a boundary wire for large areas or without a boundary wire to protect an area up to 10 feet in diameter (5 foot radius around the transmitter). Includes power supply, boundary wire and four indoor training flags with two flag bases (each holds two flags). Receiver collars must be purchased separately. Designed to pair with the CR7 receiver for cats, but will work with all DogWatch FM receivers.