1/2pcs 4 In 1 Door Alarm Security Alarm 3/15/30/60 Seconds Wireless Fridge Doorbell Sensor Alarm Features General alarm (alarm stop if door closed); Door opening chime (sounds DingDong once the door is opened)Loud 108dB alarm: Door and window alarm helps effectively deter intruders/ thieves with a loud 108 dB alarm. You can easily set the suitable mode according to your needs. Easy to Install: Simple peel and stick installation, easy to install on most freezer/refrigerator or any door without any tools. Widely Used: Magnetic Trigger Door Alarm Sensor Protecting Home Through Door Window Entrance and Suitable for Safe, Cabinet, Freezers , refrigerators, swimming pool sliding door, shop, office, apartment, hotel, etc. Specifications Battery: 2*AAA batteries(not include) Package Include:1/2PCS*Door Alarm Note: Due to different personal measurement methods, there will be an error of 2-4 cm, please understand Thanks for your support