Gold rings (bangle)

The Inhibitor Rings are golden rings worn on the wrists of Shadow the Hedgehog. Although never stated, they were presumably created by Professor Gerald Robotnik or another scientist aboard the Space Colony ARK. When Shadow removes them in the different canons, he receives an increase in power at the risk of over-exerting himself. First appearing in Sonic X, they were not named "Inhibitor Rings" until adapted by Archie's Sonic the Hedgehog comics.

History
First appearing alongside Shadow's debut in Sonic Adventure 2, the rings were not named, but at Shadow's presumed death upon defeating the Finalhazard, Sonic gave one of the rings he retrieved to Rouge the Bat.

The games eventually adapted the concept about Shadow gaining a power boost from removing his Inhibitor Rings as well in Sonic the Hedgehog (2006). When Mephiles the Dark had stolen Shadow's Chaos Emerald and replicated himself into an army, Shadow removed his rings to boost his attack power. Like in Sonic X, they are not named and there is little explanation for them. The ability has thus far only been used once.

Sonic X
The first removal of Shadow's rings appeared in the episode "Showdown in Space", in which Super Shadow removed them to boost his Chaos Control. Although called "limiters" in the Japanese version of Episode 73, there is little explanation as to how they work. It may be an inversion of how the Sonic X version of Sonic would get a similar boost from gaining a ring, and they were only removed in close proximity to a Chaos Emerald or a fake Emerald. Shadow removed them for a boost several times throughout the series. He quickly loses energy and collapses after the boost of power, or when he is without them for any period of time in battle. The limiter rings are connected to the red tongues on the black cuffs of Shadow's gloves; the red tongues disappear when the limiters are removed.

Archie Comics
Adapted from the Sonic X version, the Inhibitor Rings are both named and more thoroughly explained in the Archie comics. Shadow uses them to limit the amount of power he uses during combat and other situations. When he takes them off and uses his Chaos powers, his power is drastically boosted, but he easily becomes thoroughly drained of energy. He was first seen using this method of power enhancement during his battle against the second Enerjak. This caused his Chaos powers to increase dramatically and even match Enerjak's power for a short time, nearly tearing the whole city of New Mobotropolis apart in the process. He later used them again during a mission in the ruins of New Megaopolis to destroy Dr. Eggman's Doom Laser. In this mission, Shadow took off his rings and became Chaos Shadow, where he divert the blast from the laser using Chaos Control, and his plan worked successfully, though he nearly fell off the observatory in which the Doom Laser was housed. (StH: #182 SU: #2).

Trivia

 * Shadow lost an Inhibitor Ring at the end of Sonic Adventure 2, which Sonic gave to Rouge as a memento. However, in Sonic Heroes, Shadow still has both Inhibitors, this may be because Eggman stole the other one back, or the ones Shadow has are just duplication's.
 * Prior to his transformation in his crystaline form, Mephiles possessed two Inhibitor Rings, though they were likely to be mere ornaments.