STI 30150 Wireless Driveway Monitor (battery powered), Wireless Alert The sensor may be placed as far as 1000 feet (line of sight) away from the receiver in your home For best performance, mount the sensor on a 4x4 post, four to eight feet off the ground Additional sensors may be required for driveways exceeding 12 feet or to monitor an additional driveway Will not be triggered by animals, people or shadows Additional Driveway Monitors, Motion Alert sensors available to cover multiple areas and to expand your system