4 in 1 Mode: This alarm with 4 modes. Delay alarm (sounds 'Di-Di-Di' from 0dB to 108dB if the door remains open for 3/15/30/60s) General alarm (alarm stop if door closed); Constant alarm (constant alarm even door closed); Door opening chime (sounds DingDong once the door is opened) Loud alarm 108dB Loud: The door and window alarm helps effectively deter intruders/thieves with a loud 108dB 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 freezer/fridge or any door without any tools. Package includes 2 fridge alarms, 2 magnetic strips, double-sided sticker, user manual . The electronic instruction is on the eighth picture. Installation Note: Be sure to close the alarm and the magnetic strip, the installation distance between them should not exceed 0.78 inch. The 2 parts must be aligned by their alignment arrow. 2 AA batteries can . (Batteries are not included) Widely Used: Magnetic Trigger Door Alarm Sensor Protecting Home Through Door Window Entrance and Suitable for Safe, Cabinet, Freezers, Refrigerators, Door pool slider, store, office, apartment, hotel, etc.