Angel/Devil is an installable performance-enhancing component for Extreme Gears. Its actual appearance is unknown, though it is presented as an icon on the head-up display in the top-left corner of the game screen. Its icon is a circle with a different image on each face. On its default side, it is yellow with an angel figure inscribed in it ("Angel Mode"), and on the other side (which is revealed when Angel/Devil is activated) it is lavender with a devil figure inscribed in it ("Devil Mode").
In the game, Angel/Devil is permanently installed into only certain Extreme Gears. When used, Angel/Devil can set the Extreme Gear to one of two alternate modes corresponding to its icon which gives it a different appearance and set of abilities:
Angel Mode: The Extreme Gear turns completely white and gains angelic wings. While in Angel mode, the Extreme Gear will increase the players' chances of obtaining more beneficial items from the Item Boxes on the tracks at the cost of lowering its top speed.
Devil Mode: The Extreme Gear turns completely black and gains both devil wings and a devil tail. While in Devil mode, the Extreme Gear will increase its top speed at the cost of increasing the player's chances of obtaining hindering items from the Item Boxes on the tracks.
The mode granted by Angel/Devil depends on the face of its icon present when the player activates it; once the player has the opportunity to activate Angel/Devil, its icon will switch between the faces representing the "Angel mode" and the "Devil mode", and the face seen when Angel/Devil is activated will decide which mode will be chosen.
In gameplay, Angel/Devil and its ability will be disabled when starting a new race. To activate Angel/Devil, the player must press one of the following buttons after collecting a certain number of Rings:
Wii (remote) - sideways
Wii (remote) - forward
Wii (Nintendo GameCube Controller)
When activating Angel/Devil, the player's Rings will be reduced accordingly by the number needed to enable it and the Extreme Gear is surrounded in an orange void, indicating the Gear Part's ability is in effect. The following Extreme Gears come equipped with the Angel/Devil: