The Boost Ring is a rotating ring that allows the player to perform a Speed or Air Boost in the air. When the player jumps into one, the Boost Ring will read out a certain button prompt that usually indicates a recommended route to take: , or ? (in this case, the player can choose either). To perform Air Boost, the player must press and to perform Speed Boost, the player must press . If the player does not prompt after a short while, they will simply drop down from it.
The Boost Ring appeared for the first time in Sonic Rivals. In this game, all of the playable characters can use it.
Sonic Rivals 2
The Boost Ring reappeared in Sonic Rivals 2. It functions exactly like it did in Sonic Rivals, except that it will not show a question mark icon; in such cases, the screen will prompt both and . In addition, the player can now change their horizontal direction when performing either Boost manoeuvre off of a Boost Ring by pressing and holding left or right before pressing or (which otherwise defaults to the forward direction the player was facing as they entered the Boost Ring) as opposed to a fixed forward direction that the player was facing in Sonic Rivals.