PetSafe Original Wireless Electric Fence for Dogs, Portable for Travel Covers Up to 1/2 Acre, Waterproof Collar for Pets 8lb+ with Tone/Static (Gray), from The Parent Company of Invisible Fence Brand1 2 ACRE OF CIRCULAR WIRELESS FREEDOM: Experience the liberty that comes with our wireless dog fence, a revolutionary containment solution that covers up to half an acre. This wireless dog fence system is designed to ensure your pets' safety and security within a designated circular area, eliminating the need for physical barriers or buried wires. This boundary can be expanded further with the purchase of an additional transmitter. MOST ACCURATE