I opened and tested it once. I am selling it because it doesn't fit my home's setup. Regular price: 2300 yen each This security sensor sounds a loud alarm when a window or door is opened. It uses AAA alkaline batteries. How about it for home security, or for outdoor activities, especially solo camping, as a theft deterrent? Burglary Buzzer - Model name: Loud Alarm - Included: 2 stickers - Size: 85.5 x 29.3 x 25 mm - Function: Alarm sounds when a window or door is opened - Installation: Easy to install without wiring Thank you for looking.