            She blushed fiercely at his insinuation but forced her anger down. This was the Lucius Malfoy she’d been expecting, though she had a feeling there wasn’t much bite left between those pearly teeth. "It tracks your movement—restricts it to a predetermined area," she added thoughtfully. "While copper acts extraordinarily well as a magic conduit, it can also be charmed to absorb instead, effectively making the wearer magic-less. Even if you had a wand," she said, dropping her eyes to the fork still clenched between his fingers. He set it down, sniffing. "Any magic is re-directed into the metal. That’s why you were visiting the DMLE," she said slowly, as the pieces fitted together. "The cuff gets saturated, if enough magic is attempted. An Auror must have to take it off, to neutralize it again before the magic begins to burn too hot inside the copper." She turned her eyes back to his and had to fight a smile at his impressed expression. "What magic were you attempting, Mr. Malfoy?"