A geofence is a virtual perimeter established around your parked RV or car within a specified radius. For instance, if you've parked your RV at a campsite, you can place the Pet Monitor GPS device in the vehicle and configure a geofence with a 1-mile radius. When your RV exits this geofence, you will receive an "OUT" alert. Conversely, when your RV reenters the geofence zone, you will receive an "IN" alert.