4 in 1 Mode: This alarm with 4 modes. 1. Time Delay Alarm (sounds "Di-Di-Di" from 0dB to 108dB when door is left open for 3/15/30/60 seconds) 2. General Alarm (alarm stops when door is closed); 3. Constant Alarm (continuous alarm even when door is closed); 4. Door Open Beep (sounds "DingDong" once door is opened) 108dB Loud Alarm: The door and window alarm effectively deters intruders/thieves with a loud 108dB alarm. You can easily set the suitable mode according to your needs. Easy Installation: Simple peel and stick installation, easy to install on most freezers/refrigerators or any door without any tools. Package including 2 refrigerator alarms, 2 magnetic strips, double-sided sticker, user manual. Installation Note: Be sure to close the alarm and the magnetic strip, the installation distance between them should not exceed 0.78 inch, the two parts must be aligned according to their alignment arrow. 2 AA batteries can last for 2 years. (Batteries are not included) Widely Used: Door