The catch was that mails put me a revolutionary tax of 19 € plus 5 of the product vat. I think the package was too well documented: product description and the amount well visible. Will they be forced to pass 22?. Total that in a purchase of 23.82 € i paid 23,93 € extras to the post office. I paid it to not harm the seller who is not to blame, you 've looked after me very well and you have excellent products. Was it bad luck?.
Sensors are working. The sensitivity is low and this is for the better, since there will be no false positives. Works when above the average tapping on the glass (when the glass is broken it will work accurately. Ugly looks on the window from the side of the street, it would not be bad to have a stylized image of the vibration sensor on the double-sided tape.
Thank you to the seller.