Cerebro amplifies the brainwaves of the user. In the case of telepaths, it enables the user to detect traces of others worldwide, also able to distinguish between humans and mutants. Depictions of its inherent strength have been inconsistent; at times in the storylines it could detect mutated aliens outside of the planet, when at others it could only scan for mutants' signatures in the United States. It is not clear whether it finds mutants by the power signature they send out when they use their powers or by the presence of the X-gene in their body; both methods have been used throughout the comics.