In-ground radio fence designed for stubborn and hard-to-train pets. Features 4 adjustable static correction levels plus tone with vibration-only mode. Ideal for training hearing-impaired dogs. Can cover up to 10 acres with the purchase of additional wire and flags. Receiver is waterproof and features a low battery indicator. Works with multiple pets, additional receiver collars required. Includes transmitter with power adapter, receiver collar with battery, surge protector, 50 boundary flags, wire nuts, gel-filled capsules, test light tool, and operating & training guide.