Features: Ultra-thin design, the back of the product adopts high viscosity back sticker, which can be installed on any door and window. Material eco-friendly, meets EU test standards. High precision materials, never false positives. When the distance between the host and the magnetic strip exceeds 10mm, the alarm will alarm immediately. Low voltage prompt reminds you to replace the battery in time to protect your safety and the your family at any time. Usage Overview: The host and the magnetic strip are attached to the door panel and the door frame respectively. Turn on the rocker switch on the left side of the main unit, the door will alarm when the door is opened, and the switch can be turned off when the alarm is not required. Packing List: 2-Pack Wireless Door Sensor Alarm We only sell Wireless Door Sensor Alarm, not other items in the picture. Due to the differences between different monitors, the pictures may not reflect the actual color of the item. Due to manual measurement, please allow slight errors in size.