The Maltese Ring is an an ancient hand-crafted, ring shaped weapon appearing in the 1987 TV series episode The Sword of Yurikawa.
Millionaire Lafayette Le Drone, an international collector of old and rare weapons, sees a news report by April O'Neil which includes the fact that the Sword of Yurikawa is on display at the Japanese Embassy. He decides it must be part of his collection and dons the Maltese Ring, choosing that as the weapon best suited to stealing the sword.
Le Drone uses the ring, which shoots bolts of energy, to destroy a security camera inside the Japanese Embassy so that he can steal the Sword of Yurikawa. The ring also contains a small grappling hook attached to a thin line. Le Drone uses the grappling hook to climb out of the embassy after the theft. He uses it again to grab one of his weapons, a double-cross bow, from across the room in order to use it on the Turtles.