As soon as the door opens where there is a sale, a notification will be sent to your mobile phone so no one knows about it.

As soon as you open the door, you will be notified on your mobile phone. The product that is not allowed to be known is a door and window sensor alarm, which can be purchased at security supply stores. Door and window sensor alarms are also called door and window wireless alarms. Mainly through mobile phone text messages to send messages to prompt. Such products are generally available in security supply stores, with prices ranging from 200 to 500 yuan, with high-end products costing thousands of yuan.