Petsafe Free To Roam Wireless Fence. The Free to Roam Wireless Fence system covers a circular area up to 1/2 acre with no trenches to dig or wires to bury at a fraction of the cost of a traditional physical fence. The fence transmitter is portable for RVs, cabins, and rental houses. Just plug the transmitter into a standard outlet near the area where you want to contain your pet. The transmitter communicates with your pet's waterproof receiver collar and helps keep him in the designated area. The Free to Roam receiver collar is ergonomically designed for comfort and sized for pets weighing 5 pounds or more. Choose from 5 adjustable levels of static correction to find just the right level for your pet, plus tone only mode which warns your pet with a beep. With just a few short training sessions, you'll create a secure boundary for your pet to enjoy freedom and fun! Features Portable wireless system sets up in 1-2 hours For dogs 5 pounds and up Fits neck sizes 6-28 inches Tone-only mode alerts your pet with a beep Covers an adjustable circular area up to 1/2 acre (180 feet in diameter) Expand containment size with additional wireless transmitters (sold separately) Add an unlimited number of pets with additional wireless receiver collars (sold separately) Waterproof receiver collar Collar uses replaceable RFA-67D-11 Batteries Low-battery indicator (collar) Works with the original Wireless Pet Containment System (PIF-300) and Receiver Collar (PIF-275) In the Box Transmitter with power adapter Waterproof receiver with adjustable 3/4" collar strap 6-Volt Battery (RFA-67D-11) Test light tool Quick start guide 50 boundary training flags Short and long contact points Contact point wrench Mounting bracket and hardware