The Wireless Door Sensor is a kit of the BroadLink S1 smart home security alarm system. Paired with the S1 host, it can automatically detect any vibration or movements from your door or window and instantly alert you of possible break-in or intrusion via APP notification. Meanwhile, it also sends signals to the host and the host will make a loud alarm to deter a would-be intruder. The smart sensor can be attached easily to any window or door in your home and keep you informed of the status of your door or window. Window/Door SensorProvides an easy-to-use security solution to protect you and your family against home invasions. Smart SensorSends you instant alerts via APP notification if doors or windows are opened unexpectedly. APP MonitorCheck if your door or window is securely locked using the APP while you're not at home. Alarm TriggerSends signals to the host to trigger loud alarm to deter any intruder. NoteThe wireless Window/Door Sensor works when paired with the S1 host. Specifications Brand BroadLink Model S1 Package Weight 100g Package Size 15L x 7W x 4H cm Package 1 x Door sensor