: This "piece" is central to the plot as Greg uses it to fake an emergency to spend more time with Steven, eventually leading to the episode's climax at the Geode . Dear Old Dad

: It is a unique Gem-powered device that Pearl gives to Greg Universe so he can signal the Crystal Gems if he needs help while they are away.

In the context of Season 1 Episode 27, "House Guest," the most significant "piece" is the Warp Whistle .