Breather / Product design

We all known that when we were riding a bicycle, the volume of gas in tires was gradually decreasing. But we draw so little attention to the fact that our physical energy was draining in the process of bicycle-riding. So we thought hard over and over about how to remind us to blow up tires in time. According to basic principle of balloons, we can find that airbag is plump when gas is adequate, and the airbag begins to shrink when the volume of gas is decreasing. The change of airbag's size in the process of use makes us identify quickly the phenomenon of decrease of gas gradually
in tires, which can remind us to pump up tires.