Smart door and window sensor with instant push alerts to your phone the moment a door or window opens. Peel-and-stick adhesive installation — no tools, no drilling, no hub required. Connects via 2.4GHz WiFi and works with Alexa and Google Home for voice alerts. Compact design blends into any doorframe or window frame. Perfect for front doors, back doors, ground-floor windows, safes, cabinets, and rental apartments where you cannot install a full security system.