Easy installation and operation: Wipe a flat surface, remove the sticker, attach the alarm (batteries not included) to the door, and attach the magnetic strip to the door frame.Smart Design: The distance between the alarm and the magnetic strip is over 0.39 inches (10 mm). The alarm will continue to sound until you close the door (connect them) or turn it off (switch to the "OFF" button). It takes up very little space. It has three adjustable settings (On/Off/Set). Switching to the "SET" button causes a beep-like sound that won't scare your children or pets away without your knowledge. Switching to the "ON" button causes a loud, siren-like beep.Protect your home and office: Instantly alerts you when pets or people enter. Deter theft when no one is home; the loud alarm will scare off thieves, allowing you to sleep peacefully at night without worrying about intruders.Alarm On and Off Modes: This product will immediately sound the alarm if someone enters and opens a door or window, leaving a gap greater than 0.5 inches. (High volume, >90 dB). If you prefer to keep the door open, switch to alarm-off mode.Installation: Wipe the surface clean, remove the sticker, attach the alarm to the door, and attach the magnetic strip to the door frame. Done!