Wireless Driveway Alarm featuresThe Hosmart Motion Sensor with Wireless Motion Alert is a convenient and affordable safety / security system. 1.weatherproof outdoor sensor with adjustable sensitivity control. 2.The sensor may be placed up to a 1/4 mile from the base unit in ideal condition. 3.Alerts with light and sound when vehicles or pedestrians approach within a 30 feet radius. 4.Expandable up to unlimited sensors and unlimited receiver, it is perfect for home, business, property and work site. 5.Super simple to set up. Takes only a few minutes to set up. Easy do it yourself installation. 6.Set includes one sensor. Detects motion in up to 4 different zones, Low batteryindicator included. 7.Receiver can be plugged in using included AC adapter or can run on (4) AAA batteries.