In need of a strong durable containment system with great range then the SDF-100 by SportDOG is perfect for you. The system comes with more wire than all of our other systems and is expandable up to 100 acres. The base unit gives you great control allowing you to change the correction types among 3 different modes; Beep and Vibration with Static stimulation, Beep and Vibration only, and static only. Also on the unit you can alter the distance of the active perimeter making the warning zone bigger or smaller. The levels of static correction can be adjusted on the collar allowing customization among multiple pets. With the large containment zone of this product your pet(s) will have plenty of room to run, play, relax, and explore!