Item Bulb are reoccurring objects found within Phantom Hourglass and Spirit Tracks. They contain one specific item, such as Bombs or Arrows so that Link can easy replenish his inventory. These bulbs are usually found around areas where such items are required to defeat enemies or solve puzzles.
In Phantom Hourglass, Item Bulbs appear within the Temple of Wind, Temple of Courage, and the Goron Temple. In Spirit Tracks, Item Bulbs are found within the Tower of Spirits and throughout most of the dungeons.