Space Jump Boots

From Wikitroid, the Metroid wiki

The Space Jump Boots are a suit upgrade - of Samus' boots, to be specific - which attach to the feet of her Power Suit upon collection. They are equipped with miniature jetpack-like mechanisms that allow Samus an extra jump in midair. This upgrade is highly useful for clearing tall gaps, or for strafing & sidestepping more efficiently. This upgrade only appears in the Prime Series. While it is not visible in the first person, Samus spins for the second jump as in the 2D games' Spin Jumps. The spinning can be viewed in the Metroid Prime 2: Echoes ending sequence and in multiplayer mode.

This upgrade should not be confused with the Space Jump, a highly advanced movement system featured in the 2-D Metroid games.