4-in-1 Mode: This alarm has 4 modes. 1. Delayed Alarm (sounds 'Di-Di-Di' from 0 dB to 108 dB if the door is left open for 3/15/30/60 seconds); 2. General Alarm (the alarm stops if the door is closed); 3. Constant Alarm (sounds constantly even when the door is closed); 4. Door Opening Beep (sounds 'DingDong' when the door is opened) Loud 108 dB Alarm: The door and window alarm helps effectively deter intruders/burglars with a loud 108 dB alarm. You can easily set the appropriate mode according to your needs. Easy to Install: Simple peel-and-stick installation, easy to install on most freezers/refrigerators or any doors without the need for tools. Package includes 2 refrigerator alarms, 2 magnetic strips, double-sided adhesive and user manual. Installation note: Be sure to close the alarm and magnetic strip; the installation distance between them should not exceed 2 cm. The 2 parts must be aligned using the alignment arrow. 2 AA batteries can last 2 years (batteries not included).