Magnetic thermal detonators, created by Merr-Sonn Munitions, Inc., were essentially hemispherical variants of the Class-A thermal detonator. The device's flat side was magnetized, enabling it to adhere to metallic surfaces or be secured to a bandolier for transport. During the Second Battle of Geonosis in 21 BBY, Jedi Commanders Ahsoka Tano and Barriss Offee tried to use magnetic thermal detonators to obliterate the control center of a major droid foundrey. After Geonosians acquired the bombs, they adapted by employing a super tank to target the generator.
In 19 BBY, Tano, who was by that time a Force-Sensitive Outcast as a result of her departure from the Jedi Order, retrieved multiple magnetic thermal detonators along with a bandolier from the Pyke Syndicate's armory located on Oba Diah. She strategically placed several detonators within a sansanna spice refinery, mainly to demolish the structure, with the resulting blasts also serving as a diversion to facilitate the escape of Ahsoka, Trace, and Rafa Martez from their captivity at the hands of the Pykes.