4-in-1 Multi-Function: Four modes to suit various needs — general alarm, constant alarm, time-delay alarm (closing alarm), and doorbell. Simply press the button to select the desired function without complicated adjustments. This contact sensor kit quickly detects the open or closed status of doors or windows. Requires 2 AAA batteries (not included). Freezer Door Alarm with Adjustable Delay: Upgraded version offers delay options of 3, 15, 30, or 60 seconds. Magnetic trigger door alarm sensor for home security — suitable for doors, windows, cabinets, freezers, refrigerators, sliding pool doors, stores, offices, apartments, and hotels. 108 dB Loud Alarm for Home Security: The door and window alarm emits a loud 108 dB sound to deter intruders and alert users to unauthorized access. The chime also notifies you when children, pets, or seniors enter or exit unexpectedly. Ideal for child safety, home security, garage, mailbox, and business applications. Easy Installation: Includes self-adhesive pads — no tools required. Simply attach the sensor to the door or window. Can also be used as a door stopper alarm, pool door alarm, garage door alarm, or sliding door alarm. Low-power design ensures long-lasting operation — up to 2 years of battery life. Installation Note: Ensure the alarm unit and magnetic strip are fully closed during installation. The maximum spacing between the two parts must not exceed 2 cm. Align both parts using the indicated alignment arrows.