Keep the whole pack safe in your yard with the Basic In-Ground Fence™. This exclusive bundle comes with 2 collars and enough boundary wire and flags for yards up to 1.5 acres. Install the system in about a weekend by setting up the transmitter and burying wires around your yard. You'll place flags around your yard and train your pets where their new yard boundaries are in fun, quick training sessions over the next 2 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. Have more than 2 dogs? Add an unlimited number of pets by purchasing an extra collar for each pet. The fence can also cover yards up to 5 acres with additional wire and flags.