PetSafe Basic In-Ground Pet Fence – Includes TWO Waterproof CollarsThe PetSafe Basic In Ground Fence is a DIY boundary system that lets you create a safe, customizable play area for one or more dogs. With two waterproof collars included, you can set up and expand your dogs containment quickly and confidently. Coverage and Expandability: Creates a secure 1 3 acre wire boundary with the option to expand up to 5 acres by adding more wire and training flags. Receiver Collars Included: Includes 2 UltraLight In Ground