in 1 Multifunction: 4 modes to meet your multiple options: general alarm, constant alarm, delay (closing alarm) and doorbell, just press the button to choose the function you need without any complicated settings. This contact sensor kit can quickly detect the status of your door or window. Requires 2 AAA batteries (not included). Freezer Door Alarm with Delay and Widely Used: Upgraded versions with 3/15/30/60 seconds delay for you to choose. Magnetic trigger door alarm sensor protecting home through window entrance door, suitable for safe, cabinet, freezer, refrigerator, swimming pool sliding door, store, office, apartment, hotel, etc. 108dB Loud Enough for Your Home Security: The door and window alarm helps effectively deter intruders and thieves with a loud 108dB alarm, the open chime will alert you if children/pets/elders arrive or leave unexpectedly. It can prevent your children from sneaking out. And it is a perfect wireless magnetic security alarm for child safety, burglar protection, home, garage, mailbox and business security. The home/window contact sensor alarm comes with self-adhesive pads so no tools are needed, just stick the door alarm sensor on the door or window. It can also be used as a doorstop alarm, pool door alarm, garage door alarm or sliding door alarm. Low power consumption design, providing practical and long-term protection. They can work more than 2 years. Installation Note: Make sure to close the alarm and magnetic strip, the installation distance between them should not exceed 2 cm. The 2 parts should be aligned by their alignment arrow. Packaging: 1 piece,"