The Dogtra E-Fence 3500 is an easy-to-use and effective containment system that will keep your dog safe and secure. The underground wire contains your dog without conventional fencing that can be chewed through or jumped over. The stimulation field can be adjusted with the transmitter. The Function Selection Switch allows you to quickly change from pager/vibration to corrective stimulation with the flip of a switch: 1) In Pager + Stimulation Mode your dog will receive vibration before stimulation when approaching field boundaries. 2) In Pager Only Mode your dog will receive a non-stimulating vibration only.