Cerulium bracelets were used as a means of mind control using cerulium, tried by the Department. Their primary function was to make their wearers less rebellious. The girls who wore them also became very flirtatious, and the men entranced by them always responded very agreeably, possibly because of an aura from the cerulium. These bracelets made these girls seem more attractive.
In 2050, Drake distributed the bracelets at Magdalene Academy as part of his plan to fully control the people of London. K9 destroyed the bracelets after his friends learned of the danger they posed. (TV: Sirens of Ceres)