High Jump Boots

From Wikitroid, the Metroid wiki

The High Jump Boots (also known as the Hi-Jump) were an upgrade found in the 2-D Metroid games. As indicated by the name, the Boots allowed Samus Aran to jump much higher. In Metroid Fusion and Metroid Zero Mission, the Spring Ball is granted along with the boots.

Notably, it is often possible to completely skip the High Jump Boots in many of the games. In Metroid Fusion, sequence breaking was made nearly impossible and so the boots were required.