4-in-1 Modes: This alarm boasts four versatile modes. 1. Delay Alarm (sounds 'Di-Di-Di' from 0dB to 108dB if the door remains open for 3/15/30/60s); 2. General Alarm (alarm stops when the door is closed); 3. Constant Alarm (continuous alarm even if the door is closed); 4. Door Opening Chime (sounds 'DingDong' when the door opens) 108dB Loud Alarm: Effectively deters intruders/thieves with a powerful 108dB alarm. Easily adjust the mode to suit your needs. Easy Installation: Peel-and-stick installation for effortless setup on most freezers/refrigerators or any door without tools. Installation Note: Ensure the alarm and magnetic strip are aligned, with a maximum installation distance of 2cm between them. Align the two parts according to their directional arrows. (Batteries not included) Widely Used: This magnetic door alarm sensor protects homes, securing doors, windows, and is suitable for safes, cabinets, freezers, refrigerators, pool sliding doors, shops, offices, apartments, hotels, etc.