A telepathic inhibitor
Telepathic inhibitors were developed in 2007 (or maybe 2006?) as a result of the general-populace fear of psionic mutants. They appeared suddenly, without any prior patent work showing the lead-up to the final design. Since then, they have become one of the hot, must-have items for militaries, security contractors, and criminals around the world. There was an initial delay in their manufacturing due to the high demand, which has since evened out. They remain extraordinarily expensive, well out of reach of the average consumer. Frost Industries holds the patent and is the only manufacturer of telepathic inhibitors.
Telepathic inhibitors are worn at the ear and are often mistaken for Bluetooth or other hands-free devices. Their primary function is to prevent the effect of psionic-based mutations, such as telepathy, empathy, illusions, and dreamweaving, on the wearer. As a result of this function, those wearing inhibitors are a psionic 'blind spot' for mutants who can typically gauge things such as numbers present or the general emotional state of those around them. They can also be used in reverse; a psionic mutant wearing an inhibitor typically cannot access his or her powers for use on anyone.
Inhibitors are known to be flawed; although they typically block psionic mutations, with a great deal of effort, a mutant can learn to work through them. The time and skill needed to do so tends to vary drastically according to a number of factors, including the mutant's general strength and familiarity with inhibitors.