4 in 1 Mode: This alarm features 4 modes. 1. Timing alarm (emits a 'Di-Di-Di' sound from 0dB to 108dB if the door remains open for 3/15/30/60 seconds) 2. General alarm (alarm stops when the door is closed); 3. Constant alarm (alarm continues even after the door is closed); 4. Door opening chime (emits a single 'Ding-Dong' sound when the door is opened). Loud 108dB alarm: The door and window alarm helps effectively deter intruders or thieves with a loud 108 dB sound. You can easily select the appropriate mode based on your needs. Easy to Install: Simple peel and stick installation allows for quick setup on most freezers, refrigerators, or doors without the need for tools. Package includes 2 fridge alarms, 2 magnetic strips, double-sided adhesive tape, and user manual. Installation instructions are shown in the eighth image. Installation Note: Ensure the alarm and magnetic strip are properly closed. The installation distance between the two parts should not exceed 0.78 inches. The alignment arrows on both parts must be matched. Operates on 2 AA batteries (not included), with battery life lasting up to 2 years. Widely Used: Magnetic trigger door alarm sensor provides security for home entry points including doors and windows. Suitable for use on safes, cabinets, freezers, refrigerators, sliding doors, shops, offices, apartments, hotels, and more.