PetSafe Wireless Instant Fence Extra Transmitter System For Pet Weight Min 8 pounds Locate indoors at least 2 to 4 feet above ground level Adds an additional 1/2 acre to your existing PetSafe Wireless Containment System for increased coverage Requires a PetSafe Wireless Fence Receiver Collar to operate (sold separately) Covers an adjustable circular area up to 90 feet in all directions from the indoor transmitter. AC Adapter included Plug the transmitter into a standard outlet close to the area you would like to contain your pet Portable transmitter is perfect for RV camping and vacation homes Operating range may be affected by a variety of factors including terrain, topography and metal objects. The Pet Area cannot be changed into a square or rectangular shape Call, chat or email with our expert PetSafe US-based customer care specialists six days a week; They are waiting to assist you and your pet with your product needs PetSafe brand has been an industry leading US manufacturer of pet behavior, containment and lifestyle products since 1991, helping millions of people and pets each year Covers an adjustable circular area up 1/2 acre (180 feet in diameter) Completely wireless &amp; portable Locate indoors 2 to 4 feet above ground level