The Crown Unlimit (クラウンアンリミット Kuraun Anrimitto?) is a Keychain for Terra's, Ventus's, and Aqua's Keyblades that appears in Kingdom Hearts Birth by Sleep Final Mix. Terra, Ventus, and Aqua are rewarded with the Crown Unlimit for clearing the Foresight unto Darkness battle.
The Crown Unlimit appears to be modeled after parts of the Mirage Arena. Its handle is covered in blue stripes, its guard is comprised by five gold gears with light blue centers with a much larger, blue-white and spiked gear set at the top of the handle. The base and tips of the blade resemble the Mirage Arena teleportation hubs and are connected by a light red beam that gives off a dim glow. This beam is surrounded by a light blue, double-helix structure. The tip of the blade is further decorated by a translucent sphere with the same dim red glow as the blade.
A gold crown resembling the one worn by No Heart sits off-kilter on the tip of the blade, forming the Crown Unlimit's teeth. The Keychain has three gold links that connect to a charm shaped like a small gold crown, similar to the one on Sora's necklace.
The former part of the Crown Unlimit's name references the crowns that are incorporated into its design, while "Unlimit" may be a corruption of "unlimited", reflecting the Keyblade's power.