Thermal detonator / Legends A thermal detonator , also known as a thermal grenade , was a highly unstable grenade - like weapon popular among military personnel , criminals , bounty hunters , and mercenaries . The thermal detonator was utilized since at least as early as 4000 BBY . Description . The thermal detonator was designed to be thrown by a soldier , planted in a specific location or on a specific vessel , or dropped by a vehicle . It would then adhere to any metallic object until it detonated . The reasons for using a thermal detonator varied widely , and despite the legal restrictions of many governments , the thermal detonator saw widespread use across the galaxy . The name was descriptive of the process by which the device explodes . Inside the shell , which was generally made of thermite or axidite , was a sample of baradium , a highly volatile substance . A trigger emitted a short burst of energy that forced the baradium into a state of fusion reaction . This trigger could simply be a button . Some had a trigger , meaning that if it was released , it would set off the grenade . Once activated , the user could reset the grenade to its safe position , thus disarming it before it detonated . The result of the explosion was an expanding particle field that could atomize any material that did not conduct heat or thermal energy within the fixed blast radius ; typically five to six meters , though some had an even greater radius . Custom grenades could have a blast up to 100 meters . Unlike other grenades , a thermal detonator ' s blast would only go as far as its blast radius . After that , the blast field would collapse , and anything even slightly beyond the blast radius would be left unharmed . Most thermal detonators had fixed field yields and radii , along with timers . Some , such as those used by Imperial stormtroopers , featured adjustable timers , with settings typically ranging from 6 to 18 seconds . Variants . The different types of thermal detonators varied in power greatly . Although typically used as a grenade , many were far deadlier . Usage . For use as thrown explosives , thermal detonators used a thumb - operated trigger and a timed detonator to ensure the weapon bearer did not destroy himself . When used by a soldier , the trigger was pressed and the device was then lobbed towards the enemy . It had to be timed , so it couldn ' t be thrown back , or detonate in mid - air . When used as gravity or inertial explosives by starfighters , speeders , or mortar units , thermal detonators used a range sensor to determine the appropriate trigger time . Some could even be clamped onto things , such as speeders . Thermal detonators were sometimes used as mining tools , but other devices were better suited for the job . Some people connected several thermal detonators using a linking mechanism , which would allow them to detonate at once and increase the damage . Small thermal detonators could be inserted in a victim ' s body and set to explode when an external condition was met . In that case , the victim would die in the explosion , but bystanders would not be harmed . The explosive charge could be removed from a thermal detonator and replaced with a small ion charge , effectively becoming an ion grenade . History . By the late days of the Galactic Republic , thermal detonators had become very common and more practical than the aging fragmentation grenade and the plasma grenade , despite the fact that the Republic had outlawed them . Ironically , the Republic would use them in its army . The Separatists also used thermal detonators though not as often , during the Clone Wars . Bounty hunters were known to carry them on their belts not only to intimidate , but to use . Stormtroopers and Rebel soldiers both employed thermal detonators during the entire Galactic Civil War . Elite Stormtroopers known as Storm commando s carried thermal detonators . While she was disguised as Boushh the Ubese bounty hunter , Leia Organa threatened to use a thermal detonator during her encounter with Jabba the Hutt in a plan to rescue Han Solo . Behind the scenes . Models of thermal detonators first appeared in , although their usage spans from " " to " . "