I have the tire pressure monitor is mounted on the tires of my scooter on Sunday. Front and rear 2.2 2.4 bar. Everything was fine Monday morning. Both guards indicated green. I had a good feeling. When I saw in the lunch break after my scooter, the guard was broken on the rear tires. The top half was broken and there was no more air in the tires. I was very lucky, because if that happens while driving, then an accident is possible. I lost then immediately the other guards from the front.