The Air Tank is presented as a vertical gauge of varying design which is set in the lower right corner on the heads-up-display. In gameplay, the Air Tank shows how much Air the player has available for Air-dependent maneuvers and for powering their Extreme Gear. The more Air the player accumulates, the more the Air Tank increases until it reaches maximum capacity. Pulling off special actions and riding Extreme Gear will in turn drain the Air Tank, and if it empties, all Air-dependent actions will be disabled.
Sonic Riders series
In Sonic Riders, the Air Tank is a semi-transparent gauge with a bottom stylized as the Speed Formation symbol. The color of the Air Tank depends on the racer. Inside the vertical gauge section is a blue bar representing the Air. When there is a safe amount of Air, the Air Tank's bar is blue, but when the rider is in danger of running out of air, the Air Tank will turn orange, then red while making beeping noises. In this state, the player will not be able to perform the Air Boost.
Sonic Free Riders
In Sonic Free Riders, the Air Tank (referred to as the Air Gauge) is a transparent and simple, yet stylized gauge with several oblique gauge sections and an energy bar inside for the Air. When full, the Air Tank's bar is green, but it gradually becomes yellow, then red as its Air depletes. In gameplay, the player can also increase the Air Tank's size with the Extra Air Gear Part.