These musical lockets belonged to the sea deities Davy Jones and Calypso and was a physical memento of their romance with one another. After Calypso abandoned Davy Jones after his ten years of service, Jones sold Calypso out to the Brethren Court and carved out his own heart to cease the pain it bore him. Davy Jones would still hold onto his locket however and often harmonize with it on his pipe-organ in the cabin of The Flying Dutchman. Calypso too kept hold of her locket while she was bound in the human form of, "Tia Dalma", keeping the locket within her shack on the Pantano river of Cuba.
The two lockets were virtually identical, silver lockets with machinery inside that played a musical melody. They resembled crabs in the shapes of hearts and had the moulds of human faces on them.
Both lockets briefly appear in this film, one being in Tia Dalma's shack and the other in Davy Jones' cabin. Jones is seen playing organ to the locket's melody and it is later inadvertently used by William Turner to lull the captain to sleep.
The lockets appear most frequently throughout this film with Calypso often being seen wearing hers around her neck. Jones is once again shown playing his pipe-organ to the locket's music, causing the captain to break into tears when Lord Cutler Beckett brings his heart aboard the Dutchman. When Jones confronts Calypso in Shipwreck Cove, he makes his entrance by playing his locket in harmony with hers.
- The official-website for Pirates of the Caribbean: Dead Man's Chest gave a fictional backstory for the lockets having been once property of a Spanish heiress before being acquired by Jones and Calypso.