Pet Safe Basic In-Ground Fence Basic In-Ground Fence™ keeps your pet safely 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 5 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 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 correction if he continues. Add an unlimited number of pets by purchasing an extra collar for each pet, Petsafe Basic In-Ground Fence Extra Collar. Product Features: For dogs 8 pounds and up Fits neck sizes 6-28 inches 4 adjustable levels of static correction Tone-only mode alerts your pet with a beep Covers up to 1/3 acre with included boundary wire Expandable up to 5 acres with additional wire (not included) Add an unlimited number of pets with additional in-ground receiver collars Run Through Prevention- Correction increases if your dog tries to run through the boundary zone Waterproof receiver collar Collar uses PetSafe RFA-67 battery (included) System Includes: Transmitter with power adaptor Receiver collar with RFA-67 battery Short and long contact points for short-haired and long-haired pets 50 boundary training flags 500 feet of 20-gauge boundary wire Surge protector Test light tool Wire nuts Waterproof gel-filled wire splice capsules Product manual