Picking sensor that alerts intruders with a 105dB volume. - Model Name: Picking Sensor - Volume: 105dB - Power: 2 AA alkaline batteries (sold separately) - Instructions: Comes with a manual Seller: Keiden Sangyo Thank you for viewing. This is a security device (picking sensor). It is stated that it only detects noise from picking and triggers an alarm, but I think vibrations are also noise, so I have doubts about whether it will be difficult to react to door opening/closing or knocking. I think it's best for doors that are not usually opened or closed. There is no on/off switch. It turns on when the batteries are inserted. (There is a switch to stop the alarm) Unused, but it has been stored for a long time, please understand. If you need it, please consider it. m(._.)m ● Due to the thickness, it will be shipped folded after taking it out of the box. #SecurityAlarm