All new, Humane Contain Model X-10, Multi-function, electronic dog fence brings you the most advanced electronic fence technology for highly humane and extremely reliable operation. You don't need to guess the appropriate stimulus intensity. This system does not rely on manual stimulus levels or stimulus zones. It uses the Pulsed Proportional Stimulus System™ a proprietary technology that automatically adjusts stimulus intensity based upon your dog's distance from the boundary. This keeps your dog reliably contained without unnecessary over stimulation. Waterproof, lightweight, ultra-slim collar has rechargeable battery. The collar also features an ultrasonic transmitter that controls optional electronic pet doors, indoor and outdoor sonic fences and scat pad accessories. You may use this product as a superior, stand-alone electronic fence or mix and match the accessories to create your own custom electronic pet care system. One small collar controls everything! The system comes with a waterproof, outdoor mountable transmitter with coded digital signal, fully illuminated status panel, audible and visual wire break alarms, power boost switch and variable field width control. The transmitter also accepts an optional, rechargeable back-up battery (model B-12V-0.8) that keeps your system operational during a power outage and automatically recharges when power is restored.