Basic In-Ground Fence™ keeps your pet contained and secure in your yard. Install the system in about a weekend by setting up the transmitter and burying wires around your yard. The fence covers up to five acres with additional wire and flags. You'll place flags around your yard and train your pet where his new yard boundaries are in fun, quick training sessions over the next two weeks. Most pets learn their new boundaries quickly. If your pet gets too close to the yard edge, the waterproof receiver collar reminds your pet with a warning beep, followed by a safe, gentle static correction if he continues. Add an unlimited number of pets by purchasing an extra collar for each pet.