Set up a barrier around your garden or pool to prevent your dog from digging or getting into areas youd like him to avoid. PetSafes Outdoor Pet Barrier System protects an area 2-16 ft. in diameter. Add extra barriers to keep your pet away from additional areas. Expand the number of collars to keep more than one pet away from specified areas. Barriers resemble rocks to blend with the environment. Barriers use four D-cell batteries (not included). Collar uses two 3-volt batteries (included). Imported. Available: Pet Barrier System: Includes one barrier and one collar. Extra Receiver: Expand your system for multiple pets. Extra Barrier: Protect more than one area from your pet. Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Containment Systems.