Power Bombs are the most powerful explosive in Samus's arsenal, capable of clearing the screen of most enemies and destroying special Power Bomb Blocks. Each expansion increases your maximum Power Bomb capacity by 1. While not as numerous as missiles, they are incredibly useful for clearing paths and dealing massive damage to certain bosses.
Locations: Power Bomb Expansions are the rarest of the resource upgrades. They are typically found in very well-hidden areas, often requiring the use of the Screw Attack to break through specific blocks or a complex sequence of Morph Ball maneuvers. Keep an eye out for unique block patterns that might indicate a Power Bomb Block, as these often lead to the expansions themselves.