CREATE A CUSTOM-SHAPED FENCE: Create a safe 1/3-acre play area for your best friend with the included 500 feet of wire; Purchase additional wire to expand up to a 25-acre yard FOR PERSISTENT PUPS: Receiver collar has a tone plus vibration mode and 4 levels of safe, static correction that you can adjust based on how your determined dog responds during training GREAT FOR HEARING-IMPAIRED PETS: If you best friend has a hard time hearing, the tone plus vibration mode will help him learn his new boundary area and keep him safe in the yard DIY INSTALLATION: This do-it-yourself weekend project lets you create a fence that fits your yard\'s shape and size COLLAR FIT: The Stubborn Dog In-Ground Fence Receiver Collar is waterproof and comfortably fits dogs 8 lb and up and adjusts to fit neck sizes 6-28 inch; For dogs 6 months and older COMPATIBILITY: All of our PetSafe In-Ground Fence receiver collars (expect for YardMax) will work with this fence system; you can purchase different style collars for every pet in the family