The Speed Booster(スピードブースターSupīdo Būsutā) is a power-up that first appears in Super Metroid in Norfair right after Samus defeats Kraid and obtains the Varia Suit. It also appears in Metroid Fusion when Samus defeats Serris in Sector 4 and in Metroid: Zero Mission when Samus defeats Kraid in his lair. This upgrade also appears in Metroid: Other M.