The ultra-economical SD-2000 features a water-resistant battery-operated collar receiver to offer secure, reliable containment. Run-through prevention (correction gradually increases as your pet approaches the boundary wire) and a timeout between corrections help your dog learn his limits quickly and safely. Includes 500’ of single-conductor ground wire, indoor wall-mounted transmitter, one collar receiver with neck strap, boundary wire, battery, training support 800 number, complete installation instructions, boundary flags, and accessories. This easy-to-install in-ground fencing system provides superior performance over all other replaceable-battery systems on the market. It is ideal for yards from 1/4 to 5 acres in size. The lightweight, 2.5 oz. water-resistant collar receiver can be used with dogs as small as eight pounds and operates on a 6-volt alkaline battery (included).